GreasyV8

Hello,

New user here so if this isn't in the right place then please move it to where it should be

I recently purchased a 2003 Cayenne Turbo which I intend to make my daily driver once everything is sorted...

I drove the car back from the previous owners house (around 80 miles) and the next day when I went to check the fluids in the morning I noticed the coolant expansion tank has spots of oil in it, and I found leaking coolant from the rear of the RH side front wheel arch.

I work away throughout the week so left the car with a Porsche specialist notifying him of my concerns and had him investigate further. He pressure tested the cooling system throughout the day and then overnight and told me he could find no external coolant leaks and also noticed the coolant was murky however suggested this may be from a previous repair and that the coolant system probably just needed a flush to remove any traces of oil.
I was told there was nothing to suggest that this problem may be head gasket related.

A little relieved I picked the car up at the weekend and had the opportunity to spend a little more time with it, I noticed that after around a 10 mile drive with a few foot-down moments that when stationary/idling the coolant temperature would creep up fairly quickly, surpassing the usual 80C and past 100C at one point too. I turned the engine off as I was at my destination anyway and did not want to test it to see how far it would go!

Now I know these engines can run a little hot due to the sheer size of them but in comparison my BMW 645ci V8 ran hot too but never alarmingly/hot enough for me to be overly concerned.

I have noticed the coolant leak a few more times over the past couple of weeks, mainly when I have put my foot down once or twice on that same 10 mile journey, and through a bit of digging have convinced myself it may be the expansion tank due to the location of the leak, my only doubt is the fact the specialist was unable to produce the leak with his pressure tester, but I am wondering if there are fine cracks in the tank that only expel a noticeable amount when the system is under very high pressure as it doesn't seem to happen on a 2-6 mile steady drive with no spirited driving.

Other symptoms/Non Symptoms

No sludge under the oil filler cap that is usually present with head gasket failure
No coolant in the oil dipstick reservoir (that I can see anyway)
Noise when I turned up the cabin heating past a certain point (22c I think) - may be completely unrelated

I live in the UK and we have had a few warm days recently but overall the average is around 13 degrees celcius, surely not enough to cause the engine to run so hot.

So to recap:

- my 955 runs hot considering the majority of driving that I do
- sporadic coolant leak (consistent with when the engine has been under heavier load)
- oil present in expansion tank

Useful info about my CTT:

2003 CTT 101k Miles

- Coolant pipes replaced
- Water pump replaced (recently)
- Aux belt replaced (recently)

none of the above were replaced whilst in my ownership

I have read about similar symptoms to mine from other owners which turned out to be the oil/coolant heat exchanger and at the minute this seems like best case scenario for me...

I don't want to go down the route of blindly changing cooling system components so any help/suggestions would be greatly appreciated.

My next course of action is to flush the cooling system using a vacuum bleeder I recently whilst testing to see if the system holds pressure.

Many thanks.

deilenberger

I think a long term leak test might be in order. Does your vacuum bleeder allow itself to be used to pressurize the system? Does it have a gauge on it where you could observe the pressure?

The factory manual shows a special tool - which is pretty much a standard pressure tester designed to fit in place of the coolant cap. The instructions are:

What's interesting is the statement "The pressure must not drop." - where there is no time limit set on this condition. A perfectly sealed cooling system would give this result. Once pressurized - if the temperature doesn't change - the pressure should be maintained indefinitely.

Is this the test your mechanic did - or did he simply pressurize the system in order to look around and see if there are any immediately visible leaks?

A test for a bad head gasket where exhaust/combustion gases are leaking into the cooling system is using an exhaust sniffer - that reads the amount of CO - used over the open cooling system. If CO is detected when the engine is running - that means combustion gases are getting into the cooling system and could be causing your heating up problems. That indicates a bad head gasket or a cracked head. If this was the case - a leakdown test might reveal which cylinder is leaking.

The other condition can be where coolant leaks into a cylinder or the exhaust passage in the head. If it's a head gasket - it would be into the cylinder. Looking for this can be done by removing the spark plugs and comparing them. If one looks VERY clean - and the others look normal - the cylinder with the clean plug has a leak into it. The coolant/water going into a cylinder will clean any carbon off the plug. A further look with an engine scope (endoscope) - might show that the crown of one cylinder is carbon free. That's the one where the leak is.

As far as a leak into an exhaust passage - the test of that is an educated nose. The exhaust will have a very sweet sort of smell to it due to the coolant burning in the exhaust.

I always wondered if the water/oil heat exchangers would be a problem. I haven't really heard of any - but that's not to say it couldn't be. In that case - when you do the pressure test - the pressure of the cooling system would drop with no visible leak - and some water would end up on top of the oil. That should show in the dipstick - with the engine cold.

That's the sort of route I'd take for troubleshooting. The most frequent cause of leaks on the early V8 were the plastic coolant pipes. Those have been done according to what you were told. The next seems to be the coolant reservoir splitting along the welded seam holding the two halves of it together. That would be revealed by exposing it - removing all the beauty panels around it - and pressurizing the system when the coolant is above the level of the seam. Then look for leaks.

Good luck! There are SO many connections/hoses/fittings/etc in this cooling system that it can be a real challenge to track down where a leak is coming from.

BTW - comparing the gauge action to a BMW gauge isn't an accurate comparison. The BMW gauge is heavily buffered - meant to show "NORMAL" over what's actually an amazingly wide range of temperatures. Consider it an idiot light with a needle. All is well until all is bad. BMW did this because they use the engine temperature - purposely changing it over a wide range - to control combustion and hence emissions and performance. They didn't want the owner running to the dealer every time it moved off middle - so it mostly always sits on the middle position until it suddenly swings to the right and steam is coming out of the cooling system.

The Porsche gauge on the 955 bears a closer resemblance to reality. Probably still has some buffering - but no where near what BMW uses. The newer Cayenne (958 series) seems more heavily buffered - and uses an electronic-assisted thermostat to control the coolant/engine temperature.

BTW - thanks for taking the time to post a coherent description of the conditions observed - and questions asked rationally. As I usually say - better questions get better answers. If you use numbered paragraphs people will tell you I get absolutely giddy.

nodoors

Don has great advice. I would do the following things first:

1. Get a bluetooth dongle and app so that you can monitor the actual temps your car is hitting in real time. Knowledge is power.
2. Flush the system again to be sure there is absolutely no more oil in it. Then monitor how quickly the oil returns into the coolant.
3. Remove the expansion tank and visually check it for leaks.

If I were a betting man you have a thermostat that is not opening at the correct temperature or only partially opening. Then the coolant system is hitting a high enough pressure for bad things to start happening. ie the leak at the expansion tank and oil possibly coming into the system via heat exchanger. It is pretty common for things to hold fine until they hit certain pressure that is beyond spec. Once something doesn't hold, you should consider it compromised. Things will likely get much worse quickly if you drive it much this way before resolving it.

I had a similar thing happen in my LS1 which resulted in the higher temps opening a pinhole leak in the radiator which was very difficult to find and also caused the power steering cooler

nodoors

...to start leaking coolant into the power steering and power steering fluid into the coolant!

CTTS520

I hate to recommend a repair on a hunch, but, unless it's fairly new, the coolant expansion tank is a good place to start. Solved all of my problems until the water pump went out. It is a 90 dollar part, an easy DIY, and a well documented source of leaks. Can be done without having to flush the coolant. If that fixes it, drain the old coolant and put in some new coolant. I had the dealer flush the coolant for me because I did not want the mess or disposal problem.

user 83838290

I second the expansion tank and thermostat. And also check if your front fan comes on when you hit AUTO on your AC. If not, you also need to make that work as well (there are two fans, you can find the appropriate thread on the fix if you search)

GreasyV8

First of all can I just say a big thanks for all the replies I've had so far I never expected such a variety of suggestions so thorough and soon after my initial post

Hi, the pressure tester I purchased is an Airlift II system (I'll try to upload a picture shortly) It does indeed have a gauge as part of the system which was one of the reasons I was so eager to purchase it, a bit of a 2 in 1 tool in my eyes.

I purchased the Porsche workshop manual as I'm a big fan of DIY and I too noticed the 'special tool' which is essentially just a pressure tester. I will use the airlift tool and keep my fingers crossed that the coolant system does not lose pressure as I can imagine finding a leak is great fun.

As far as I'm aware he just tested the system for leaks and did not check for loss of pressure, all due to credit to him and his company however as he was fully booked all week when I took the car to him and he managed to squeeze mine in for a quick check-over.

I'll do what I can on my own but failing no further information is gained I will book the car in for a leakdown test as you have suggested.

After I test the coolant system I will then move onto the spark plugs, I have a diagnostic tool which told me "Ignition coil E" had failed if I remember correctly (I'm not currently with the car) and I have an endoscope in the garage which I can utilise to check the cylinder.

The reason I thought it may be the oil/coolant heat exchanger is I found a post online from someone who was having similar problems to mine (oil in coolant reservoir) long story short he changed the head gasket and it ended up being the heat exchanger all along.

I made sure when purchasing the car the coolant pipes had been replaced and I have the invoice (For the sum of £3,000!!) as part of the history from its time with a Porsche specialist. I'm convinced the expansion tank is to blame for the leak due to the location and as I already have the majority of the trim pieces removed so I'll go ahead and at least inspect that thoroughly if not just replace it altogether.

Thanks, I hope I can gain a bit more information through the checks I'm about to undertake.

That sound's like the BMW I know, they have some interesting designs that's for sure.

Ha, I completely agree, it's extremely difficult to diagnose a problem with some engines when you're stood in front of it - never mind from across the world through a computer screen with no knowledge of previous work undertook or the life the car has lived.

I'll keep you posted and hopefully take some pictures too.

Hello, have you got any suggestions of the sort of dongle/system I should get? I've seen a lot of positive reviews about the durametric system's and I do need a system that can tell me the transmission temp (for when I change the trans fluid) but I also don't want to spend £400 for something that will spend most of it's life in a toolbox!

That is job number 1, I'm very interested to see IF the oil returns and how long it takes to fowl again.

That will be job number 2, unless it presents itself during the pressure testing from the Airlift tool.

I also had a hunch the thermostat may be to blame as it could be sticking and not opening when it should, such a cheap part to replace and would have been done by now if it didn't require removal of the intake manifold

Your absolutely right and that's why I am eager to solve the problem asap to avoid it getting worse and causing further problems, the list I have already is more than enough

Thanks for your suggestions!

Hello,

The expansion tank being replaced is pretty much a dead cert now I think, as you say various people have experience it leaking and it is a relatively inexpensive part to replace, I have a new coolant cap coming from porsche any day now which would sit rather nicely atop a new tank I think

I'll flush the coolant myself this time as I've got my shiny new vacuum bleeder but I concur with your suggestion, for the labour prices charged for such a task it is simply a lot less work to have someone else do it!

Thanks!

Hello,

I know the main fan comes on fine as I have heard it pretty much every time I turn the engine off, however I will make sure to turn the AC on and check that the relevant fan is operating (as you can imagine I don't have much use for the AC in the north-east of england)

Thanks, I'll keep you all posted!

user 83838290

Even at -10 celsius can the car become fairly hot w/o that fan running if stopped or moving slowly. BTDT

deilenberger

As far as a diagnostics tool: https://rennlist.com/forums/porsche-...ble-again.html

Much more reasonably priced, especially considering it isn't limited in the number of cars it can scan (Durametric DIY one is limited to 3 VIN#), plus it covers other manufacturers. It's also super easy to use with a smartphone app - so you can carry it along in the Cayenne for a spur of the moment diagnosis..

I have a Durametric that hasn't been plugged into the car since I got the ICarScan.

GreasyV8

Hello, I had the chance to get some work done on the car and do some digging.

First off I bought a new expansion tank and coolant cap so we went in and changed that over first. Pretty straight forward and no need to drain coolant, lost a very small amount when pulling tank out but that was it.


Photo of the engine bay with tank removed



Wider shot of engine bay with tank removed



Shiny new tank and coolant cap ready to be installed (couldn't believe the size of this thing when he brought it out at the parts store!!)



Old tank, no noticeable cracks really



The side in which I think coolant has been escaping - Like I mentioned before it didn't use to dump a lot of coolant but after some harsher driving coolant would escape under pressure almost, so I think once the pressure reached a certain point coolant was escaping through this join. Let me know if you think any different.




Whilst doing this job I noticed something interesting... My torque arm bar was well... not secured at one end It had the bolt running through it, but no nut on the end so was free to rattle around as it pleased. Strange as I never heard any unnatural rattling/knocking or felt any vibrations. However shortly after realizing the nut was missing I noticed both rubber push fit bushes were absolutely shot. So even if it was secured the vibrations would've continued through anyway and it wouldn't have done its job properly.

This is the end that WAS still secured in place. Notice the cracks in the bushing


This is the end that WAS NOT secured in place, the bush again is completely ruined.



Closer image of the unsecured end's bushing.


Torque arm removed - I think I need a new one?



Getting side tracked again I then pulled an Ignition coil from the left side of the engine (as you look at it from the front) and to no surprise at this point it had a large crack running from top to bottom and smaller cracks along its width.



First ignition coil pulled, not in good condition!



First ignition coil again, further cracks.

At this point I went and pulled the spark plug from the same cylinder, which by the way had quite a bit of oil in it (I'm right in thinking this is due to the rubber spark plug seals that come as part of rocker cover gasket set cracking or is it something worse?)

Then, I moved immediately over to the other side of the engine (Right hand as looking from the front) and pulled coil/plug. The only difference being on this side there was no oil in cylinder, to the point where the spark plug actually squeeked along its threads due a little build up of rust/general metal on metal friction.




Second ignition coil, this time from the other bank. Almost identical in it's cracks




Second ignition coil, further cracks.




Spark plug from the second bank, not the worst I've seen but not the best either!

The strange thing is how smooth the car runs considering I imagine all of the ignition coils are cracked and in need of replacement. Anyway that is another job to add to the list along with the plugs and torque arm.

This far in I noticed the radiator had debris covering its bottom half aswell as the two smaller rad's on either side (which are for the turbos?) so I went ahead and pulled the front bumper to get unrestricted access to those so I could give them a good clean out, few fiddly torx screws and a bit of force but the bumper eventually popped off.



Cayenne with bumper/headlights removed

Another reason for pulling the bumper was to get access to the bracing bar beneath it that cover the radiator drain plug on my model, the reason for that being when I tried to remove the drain plug by hand it was so brittle the head of the plastic screw snapped off in my hand with minimal force and it would've been impossible to drill it out with the bumper/bar in place.

So that's as far as I've got with the car from a few hours work yesterday. Today I will be drilling the drain plug, dumping the old coolant, using the Airlift II vacuum bleeder and filling the cooling system back up. I will also look at pulling the other 6 coils/plugs in order to look for the steam cleaning I was told about that would suggest coolant leaking into one of the cylinders.

Any other suggestions while I'm this far in?

Parts/work needed:

8 x Ignition coils
8 x Spark plugs
Both rocker cover/cylinder gaskets replacing
Torque arm replacing

Plus around 50 other jobs on various other parts of the car

nodoors

You are on the right track and your theory about the leak in the tank seams under higher temps (PV=nRT) is on par. Everything you posted is very typical with the plugs and coils. Especially the interior leaky valve gasket around the plug holes. Just wait till you get to the #3 and #7 cylinders. There will probably be a lot more oil on the top of those plugs.

Get some good shots of the other 7 plugs. While you are at it, it doesn't hurt to drop a borescope in each hole and take a looksee and or run a compression test just to know the health of your engine.

Double check your horns while you have access. They like to fill with water and die pretty commonly.

Those intercoolers are very dirty. Be careful with all the fins when cleaning! Simple green is my favorite degreaser for cleaning something like that.

GreasyV8

Update:

So, I haven't had much time with the car recently however after the expansion tank was replaced I left the car with my dad who then filled the cooling system with pure water, and then ran the car through the week whilst I was away, intending to clean out the oil contaminated cooling system before weput in the fresh coolant system using my coolant bleeder the following weekend.

There were no more coolant leaks around the car which was obviously a positive sign and the car was apparently no longer running hot so we thought we were onto a winner, only at one point my father said the temperature shot up whilst driving but he assumed this was an air pocket from when he refilled the system with water (he didn't use the airlift system I bought because we didn't have the correct attachment for the compressor). A few days later and just before I returned to see the car he was returning home when the low coolant warning appeared, he pulled the car home and noticed a trail spanning the length of the court and that the coolant was bubbling over, suspecting another cracked expansion tank due to pressure he investigated and noticed it was just the blow off valve expelling the excess coolant down the right hand wing of the car.
So, whilst we wait for the correct attachment to arrive for our compressor so we can eliminate all the air bubbles next time we fill the coolant system, I have decided I am going to do a leakdown, compression and combustion test.

currently I don't have any of the equipment to do this so before I go out and buy all three I wanted to ask, if I buy a leak-down tester, can it also do the job of a compression tester? Or do I need to buy three different tools, each for it's different application. Simply because I don't want to buy all three if the leak down tester can perform two jobs.

Thanks in advance!

GreasyV8

UPDATE: 22/05/2017

I managed to get some work done on the car at the weekend, comprising of a compression test and a head gasket leak test.

Firstly the compression test, I followed the instructions exactly from an article on Pelican Parts website, running the car to temperature before shutting the engine off, allowing to cool for 5-10 mins before pulling all coils, plugs and fuel pump fuses. First of all here is an image of what all the plugs looked like once removed.








As you can probably work out, I have numbered the plugs and orientated them upon removal as if you were stood facing the car from the front bumper looking down to the rear, so number 1 is the first cylinder on your right hand side.

They all look pretty uniform in their appearance however some cylinders had quite a bit of oil at the bottom and some were completely dry. Number 1 and number 5 had oil in as you can see from the threads, the others had none/very little.

Some also had bits of rubber stuck on the side which again I put down to failed spark plug gaskets.

So, onto the compression test results - I did the same thing for each cylinder (screwed in the tester to the cylinder, throttle to the floor, cranked engine until the needle wouldn't go any higher) and here are the results.

REAR of car

8 - 130 PSI ----------- 4 - 144 PSI

7 - 134 PSI ----------- 3 - 140 PSI

6 - 130 PSI ----------- 2 - 144 PSI

5 - 148 PSI ----------- 1 - 144 PSI

FRONT of car

I haven't been able to find out what the base PSI should be for this engine but I do know that as long as the results for each cylinder are within a 15% range then this is normal, please let me know otherwise if this is wrong.

Next I moved onto a head gasket leak test using this tool:



This was the big test and the one I was most concerned about, after finishing the compression test I put the car back together and ensured it started and ran as it should, which it did.

I then inserted the bung into the expansion tank (with a little tape wrapped around as it was just too small) and started the car again, after a few minutes the mixture was still blue and I was starting to build serious hope that it wasn't the head gasket that was the problem, the car hit temp and still no colour change but then around 8-10 minutes into the test I noticed bubbles forming in the gasket tester and it started to look like it was boiling, the mixture very rapidly turned from blue to a undeniable yellow.

Obviously I was gutted that it did turn yellow indicating a positive result and meaning the likelihood of a bad head gasket.



My next course of action is to ring a few local Porsche specialists to get the car looked at with the intention of getting a gasket replacement, but before I do I have a few questions...


1 - How much should I be paying for a replacement on an engine like this? (I'm informed that the engine must/should be removed)


2 - What other things should I factor into the price to get replaced if/while the engine is out? (Motor mounts, valve cover/spark plug gaskets, coolant T's etc?)


3 - What other components could be damaged due to the engine over heating and blowing the gasket? (Other than cracked/warped heads)


Just as a repeat, the car is drive-able as long as it is kept off the turbos and isn't pushed (I'm not driving it) and the problem of overheating only seems to occur when the car is used over 2500 RPM.


It's obvious to me now that there was no way the previous owner couldn't have known about this problem and has happily sold a duff car, I'm just frustrated I didn't spot the warning signs on purchase.. The car performs flawlessly when driven it's only once driven for a period of time either boosting or sat in traffic you realise something is wrong

nodoors

Sorry to hear the news. I don't know the conversations you had with the PO when purchasing, but it definitely seems likely he knew he was handing you a pissing baby. Especially considering the recent work that had been performed which did not fix the problem which likely resulted from an overheat as you probably know.

In response to your questions:

1. I do not know UK prices, but in US dollars it looks something like this:
-A junkyard pull with medium mileage will be 6-8k
-A full rebuild at a specialist 20-25k
-A Pcar dealer... you don't even want to go there

You should be able to find a good indy mechanic who will pull and replace the motor for 2k-4k. As you probably know this is the kind of fix that actual parts are cheap and it is almost entirely labor, so the prices fluctuate wildly based on how much people value their time and their experience level.

2. I think you pretty much covered the big ones. Probably want to check in on the health of your O2 sensors since they are tough to get to as well.

3. You could have burned valves as well. It is time to perform a leakdown test to double check them, but you will visually be able to inspect them as well when the heads come off to install the gaskets. Since you now know you have this issue, you may want to also perform another compression test, but do a wet one (putting a little oil in the cylinder) to see if those lower numbers on that one bank are affected. This will give you a little more info on if the rings also have issues or if the compression numbers are lower due to gasket or valves. If the wet test bumps those low numbers all up, you will want to know the rings are bad before going through all the effort of just the gaskets.

phatz

sorry cousin