Jaycote

Hi everyone.....I picked up a 2000 996 w/ 90K miles about a month ago, and I cannot seem to diagnose or solve the problems that I have been experiencing with it. I either bought a POS car, and screwed myself, or I'm being paranoid, perhaps a bit of both. I purchased the vehicle in Ohio and drove it to my home in Rhode Island. My first mistake was not to get a PPI. I felt confident that the prior owners had maintained the vehicle well, as it had it's IMS replaced, a ton of preventive maintenance, and extra things that a careful owner would do. The dealer advertised it as a very well cared for vehicle that needed nothing. On my way home after the purchase, I got Check Engine light, and a flashing temp light. Code was Random Misfires and Misfire on Cylinder 1. Over the next two weeks, I'd drive the car sparingly, and would fill the coolant with about a quart of water/antifreeze every time I got in the car. I did not see any visible leaks or puddles at all, until a few weeks later, although I could not pin point its exact location. I purchased a new Cap, and problem did not solve itself.

My first fix was to replace the plugs/coils, which I did myself. It was my first time doing this, but I followed DIY instructions and felt confident I did it correctly. For the next 50-100 miles, I got no check engine light and felt relieved, although it soon came back, with a Cylinder 1 Misfire code. The coolant reservoir or hoses continued to leak, and I began to see puddles under my vehicle after a spirited drive. Last week, I replaced the Coolant reservoir expansion tank. The hoses looked to be in good condition, although I replaced all of the clamps on them. I did my best to manually burp the system but I don't believe I did it 100% correctly, because the coolant levels were not dropping like the instructions stated it would. I left the valve open and have driven it around like that, slowly adding coolant as needed. For the first two days, no drips or leaks were apparent. However, it now is leaking small amounts onto the ground. I originally believed I was topping off the coolant with too much coolant, and it was just an overflow, but now the coolant is well below the MIN mark, and it'll still leak underneath the reservoir tank onto the ground (although I can't pinpoint where exactly the leak is coming from).

My car starts up and idles a little rough, the check engine light will flash a bit, then go solid. It's now showing misfires in 4 different cylinders. When driving, sometimes the car is accelerating very roughly, and shakes a bit, although other times it's as smooth as butter. I'm not sure of what my next steps would be. I'm unsure if the cylinder misfires are a result of coolant leaking onto them from the constant leaks I was, and still, having. I'm trying to address the coolant situation 100% before I take the next step. I'm not sure if I should do the plugs/coils AGAIN, or if they are fine. I was budgeting $1,500-$2,000/year on maintenance and it seems as though I can hit that number fairly quickly, without making any progress.

Any suggestions as to what my next steps should be? Should I take it to a dealer, and have them diagnose? Would they be able to diagnose it and tell me exactly what needs to be done, or would they be doing process of elimination and charging me an arm and a leg to do that? I want to enjoy my vehicle and feel confident behind the wheel, but I have knots in my stomach every time I start it up, and a nagging feeling that I purchased an $18,000 car with a bad engine. I previously owned an '05 Boxster S and drove it from 55K-95K miles with no issues whatsoever. I was hoping to purchase an older 996, and replace parts as they fail, and keep up on maintenance, and use it as a learning experience and really become involved with the car. However, I've had it for less than a month, and cannot get it inspected and drive it as I wish, until these issues are sorted out.

I appreciate any help and/or suggestions!

Blue Chip

First - I would call the dealer that you bought it from and give them a heads up. Tell them what you did. If they aren't a Porsche dealer - I would consider bringing it to a qualified indy for diagnosis - and do so on a flatbed. I wouldn't drive it again. The coolant / misfire issue may be related though a situation known as 'intermix.'

Again though - I think I would start with where you bought it and explain the situation - give them the opportunity to, perhaps, do the right thing.

dporto

It's going to be tough dealing with the seller being that they're in Ohio... I think the first thing to determine is if your "leaks" are internal or external. It seems like you're finding coolant on the floor so hopefully
it's nothing "bad" (internal leaks are bad...). It's possible you just have a/some loose clamp(s) or bad hoses that only leak under pressure. If I were you (and you have a decent work space) I'd get it up to temp (by driving) and then get it up on jack-stands and pinpoint the leak(s) - once you've found them, you can figure out how to fix them. The misfires are a little more disconcerting - since you've already replaced plugs and coils, the wires would be the next
possible problem... Judging by my experience, I'd stay away from dealerships unless you're prepared to spend a lot of $. Try to find your self a "good, trustworthy" independent Porsche specialist who knows water-cooled (M96) engines. Good Luck

Paul Waterloo

Where have you found the coolant leaking? Right side, left side, etc? Got any pictures?

I had a similar issue with my 99 when the expansion tank cracked then dropped coolant. Ultimately it took out the coil pack for cylinder number 1 and I had the same issues you are referring to with the flashing check engine light, once I changed the coil pack, I was good to go.

Hopefully it's not intermix.....and just a leak. Please post more details of the location of the leaks. What type of clamps are you using? The original OEM clamps or new hose clamps?

spruden

Uggh - bummer that you've had such a bad experience. Clearly you have issues that throwing more parts at the car won't immediately solve. I would find a good, trusted local independent shop to do a "post purchase" inspection. You missed the opportunity to do this before you purchased the car - that's water under the bridge. Get some professional advice from someone who is an expert on this platform. Your symptoms can have a wide number of root causes, some inexpensive some expensive and invasive.

DBJoe996

Obviously you need to determine where the coolant is going. Get some ultraviolet dye and put it in the coolant tank, run the car up to temperature and drive for a bit of time. You might have to get a radiator shop with a lift to help you out. A black light will pinpoint where the coolant is leaking. If you park in the same spot every time and can locate the puddles under the car, it would help us help you. Think of the space under the car and engine as quadrants, i.e., left front, right rear, and also under the engine, back left (AOS), front left (water pump, AOS coolant lines, expansion tank, main coolant hoses), back right (AOS coolant line connector, a square plate covering a coolant gallery) and so on. Given some rough running, misfires and loss of coolant, I would highly suspect the AOS.

Jaycote

You guys are awesome...I appreciate all the quick replies. The dealer that I purchased this from is a small business and he was a so called "Porsche Guy". The records on the car were excellent, for the first 60K miles, so I felt comfortable that I was dealing with an enthusiast who happened to have a small business selling cars, which made me feel comfortable with him, and the prior owner spent money on things like VIN etching on the windows, and performed maintenance and updates before he really needed to. However, the second I left his lot, is when I experienced post purchase regret. there were numerous issues with the paperwork, post purchase, and this guy turned out to be a jerk. He promised to mail me a tax form that I needed, along with a copy of the title, the following Monday. After 10 days I had not received the paperwork and I called him. He said that he would "try to get it out next week". Which would've been three weeks after he had originally promised. When I told him I wanted him to mail them out TODAY, he said "it's my birthday and I'm not going to the office", and that "I have 40 days, by Ohio Law, to mail you the documents, and I'll wait until Day 39. Needless to say, I was ready to pay him another visit and show him what I thought of him at that point! I could go on about that, but it's water under the bridge at this point. I learned my lesson and would never purchase a vehicle without a PPI, EVER. Needless to say, he will not give me a break and he won't care about my issues. When the check engine light came on, I was about 20 miles away from him, and I asked him if he had a scan tool. His response was, "I do, but you can go to AutoZone and get it read there". So, he was not concerned with helping his customer out, or ensuring that his customer was good to go for a 1K mile drive home.

Regarding the location of the leaks, before I replaced the expansion tank, the leak was coming from the rear drivers side quarter. I could visibly see a small drip at the clamp of the larger rubber hose that connects to the expansion tank and goes straight down towards the bottom....I'm unsure what it's connected to at the other end. I don't know if the leak was from that specific area of the old hose clamp, or if it was dripping from above. I replaced all of the clamps on those hoses with the newer style that have a screw on them (sorry I don't know the terminology). Now, the leak is not coming from that previous area. It is coming directly underneath the middle of the expansion tank, onto the ground, although I'm not sure if it's coming from the tank itself or from a hose that is in that area. When I had it up on the lift, prior to the installation of the tank, I could not see any visible leaks, and nothing dripped onto the floor. It was immediately after a 35 mile drive, so the engine was up to temp.

Paul Waterloo

It sure sounds like you have a coolant expansion tank crack. Here is when my original one failed:

https://rennlist.com/forums/996-foru...ant-issue.html

And here is when the replacement one (non-OEM) one failed about 8 months later, this is when I had the same issues that you had:

https://rennlist.com/forums/996-foru...1-misfire.html

Here's my post that shows the vacuum system to get the coolant system filled.....really suggest this:

https://rennlist.com/forums/996-foru...-oil-leak.html

Read those three threads....a lot of info in there, and most likely will help you sleep better.

NY_Swede

I had a coolant leak on mine from the coolant side of the AOS, one of the fittings broke after a spirited drive in the mountains. Can you get under your car when the engine is at idle? I could see a wet fitting from underneath the car right against the fire wall.

Its a B*tch to get to, but the AOS can be replaced without dropping the motor if that's the cause of the leak

808Bill

Take it to someone that knows these cars and save yourself before it's to late!

cds72911

In my mind you (or a dealer/indy) need to systematically troubleshoot the issues, not just guess and throw parts at it.

The dealer is likely to cost a fortune to troubleshoot. If you have a good local independent Porsche guy, that could be a good route. If you're mechanically inclined, you can do a lot yourself with a little time and some tools.

First of all, I'd slow down and take a breath. It may not be as bad as it seems. If the coolant is on the floor (not lost into the engine), it probably isn't that huge a deal (i.e. not a d-chunk/intermix/failed oil cooler/etc.). Set aside the standard 996 paranoia/fears and approach this logically.

These cars have tons of hoses (I just replaced all of them on my 2000) and more than twice as many places where they could leak (both ends of every hose where they join another line, and anyplace in between). At almost 18 years old, who knows what rubber bits could be failing. Mine were all in pretty crappy shape (more miles, same age).

If it is just coolant reservoir, sensor, hoses and/or clamps, it is simply a matter of removing and replacing the failed parts, refilling and retesting. The coolant reservoirs are known trouble spots as these cars age, so if we're playing the guessing game, that would have been my guess. If you replaced it (I think you said you did) then I'd pressure test the system and see what leaks remain.

This is pretty easy with a coolant fill tool like an Airlift (I have an off brand called OEMTools from Amazon, but I should have purchased the UView AirLift for a few more bucks: ~$100-120. Why? The OEMTools one as shipped doesn't fit under the spoiler lift assembly, so you need to move the gauge to a different position to make it usable) that you can use to slightly pressurize the system to see where the leaks are coming from. You'll (want/need) it to fill the coolant anyway - these cars have all kinds of air pockets, and this tool allows you to create a slight vaccum and fill the coolant fairly easily.

Probably not in this case, but I'd also think a little about what you or the previous owners have done to the car recently to see if any of it may have unintentionally caused the issue (I can't tell you how many times that ends up being the issue for me). Make sure the coils are seated, and that the electrical plugs are also snapped in firmly.

If your coil packs are cracked it might be causing your misfire when the coolant wets them. I think this is another age related issue on these cars. They're not too hard to replace (as you know, if you've done the spark plug tubes). Then again, if you address the coolant leak this may not be a huge deal.

Who knows, it could even be a failing water pump weeping on the floor through the weep hole...

What I wouldn't do is drive it until you figure it out. You can make a simple problem (minor coolant leak) into a big problem (fried engine due to overheating) if you don't do this right.

Or you can sell me the roller really cheap, and I'd be glad to let you know what the issue was.

PS. The flashing temperature light is one of several issues - coolant level, engine air temp sensor and cooling fan failure or some combination. You should google this one to get the details. If you unplug the coolant level sensor electrical plug under the reservoir and the light goes off, it is either low coolant (or a failed level sensor). You can easily test the engine air temp sensor with a heat gun (be careful) and a IR thermometer. If the fan comes on (over 170 deg F, if I recall correctly) and runs then it is unlikely to be the air temp sensor or the fan. Be careful reseating the air sensor in that rubber grommet, it is a PITA to get to if you drop it into the cavity on top of the head.

ZuffenZeus

How did he act BEFORE you gave him $18,000? Probably a 180 degree attitude, huh?... like overly embellished the "Porsche experience" and the car was amazing example of a 911 yadda yadda yadda???

Not trying to add insult to injury, but unless you have something in writing regarding the condition of the vehicle or if you have any documentation that would make the transaction fraudulent, then you don't have a leg to stand on with this guy. An oral contract or car salesman's oral guarantee is about as good legally as the paper it's written on. Did you sign a bill of sale that designated the car was sold "as-is, with no warranty or guarantee"??? Try to look on the bright side... this car may not be in such bad condition, and as others have mentioned, it would be wise to take it immediately to respected Porsche shop and have an estimate done for repair. Let's hope the engine does not have a serious problem like a cracked block.

bpu699

Before you go any further drain some coolant and some oil into two separate glass jars.

If the coolant and oil look normal, that's a great sign. If either looks like chocolate milk, that's a bad sign.

Report back.

5CHN3LL

Buy or borrow a Durametric. One guess is that someone blew a downshift and over-revved the engine, and the timing is now pooched. The range 2 ignition count could prove or disprove this and might be helpful monitoring engine parameters to perhaps understand why it's running so poorly...

rolex11

Check the internal hose connector in the hose that drops down from the expansion tank. There is a plastic connector used that can crack and leak coolant even though the connector doesn’t break off and the hose visually looks fine.

It took me a week to find this leak as it only leaked when pressurized and it was a pin ***** stream of coolant shooting from it that was barely visible. Not to mention that it shot about a foot away from where the connector was and fooled me as to where it was coming from.

If you replace it you might consider using a brass hose connector that will never fail due to cracking.

Just a heads up, my car actually had 2 leaks. Kind of hard to explain in writing where the 2nd leak was, but it was even harder to find than the first. But if you PM me, give me a number to call, I can talk you thru it so you can rule it out.