Rennlist - Porsche Discussion Forums

Rennlist - Porsche Discussion Forums (https://rennlist.com/forums/)
-   928 Forum (https://rennlist.com/forums/928-forum-69/)
-   -   Heads and Gaskets guidance (https://rennlist.com/forums/928-forum/774101-heads-and-gaskets-guidance.html)

MainePorsche 09-02-2013 02:07 AM

1 Attachment(s)
..

j.kenzie@sbcglobal.net 09-02-2013 09:52 AM

yep.

LazerSquid 09-02-2013 10:39 PM

Is there any way to test for a cracked block? I'm buying my tools for all the tests you told me to do tomorrow and if there's anything I can use to test for that I'd like to know before I get the tools. Or is that even a possibility? After checking the oil cold it returned to normal viscosity and level so I think I was just being a dumb ass and getting to excited when I said there was water in the oil (sorry bout that). But the missing coolant is still very real, and while id assume its the head gasket I don't want to mark cracked block off the list just yet. I have more free time over the next few days so I'll be able to run all the tests and let you all know what I find.

If it ain't broke, I'll fix it 'til it is

dr bob 09-03-2013 02:01 AM

Water in the oil looks a lot like a waek chocolate milkshake, and and oil smape drawn from the drain starts out as coonat and changes to oil after the coolant drains. IOW, the oil floats on the water/coolant when allowed to settle. If you are looking only at the dipstick, it will look like all oil since it only goes a couple inches deep.

Drain the oil sump and decide if there's coolant under the oil. Put fresh oil in (doesn't need to be anything special), pull the ignition and fuel pump relays, and the plugs, and do the compression test with no coolant added. A cheap parts-store gauge is fine at this point. Some chain stores will rent you one for free with a deposit. Make sure the battery is charged. The compression test will tell you if there's a gasket, head, valve or block failure. If you have a weak hole or two, you know the engine needs to come out. You'll be able to see the failure once the heads are off. Don't spend on a leakdown tester at this point, focus on the compression numbers and report back.

LazerSquid 09-03-2013 02:04 AM

Alright, I'll do that. Over the next few days I plan on cleaning all of the electrical grounds, replacing all the fuses, draining/replacing the oil, doing the compression test, and going through some of the other tests other users mentioned. How can I tell the difference between gasket, head, valve, or block failure with a compression test?

Mrmerlin 09-03-2013 02:14 AM

Please follow to the letter what I posted in post 32,
after you do that please post the results of what you found .

NOTE you keep asking for answers and provide no information on what has already been suggested to do,
if you wont follow these directions it will become a cat chasing its tail repair procedure,
and nothing will be diagnosed and or fixed properly

from post 32

you would be wise to remove the plugs take a picture and post it,
then do a compression test,
then remove the aircleaner and inspect the intake for oil puddles,
you may be sucking oil into the intake and not have a HG issue.
but rather a water pump /thermostat issue.

It would also be a good idea to get another 928 mechanic to look at your car,
as misdiagnosis will only cause you to fix something that may not be broken,
we can only do so much on guessing ,
the more info you provide adds to the diagnosis being closer to correct for your situation

dr bob 09-03-2013 02:22 PM


Originally Posted by LazerSquid (Post 10731423)
Alright, I'll do that. Over the next few days I plan on cleaning all of the electrical grounds, replacing all the fuses, draining/replacing the oil, doing the compression test, and going through some of the other tests other users mentioned. How can I tell the difference between gasket, head, valve, or block failure with a compression test?

Beyond what MrMerlin recommends, I'd start off with replacing the oil, pulling the plugs (with pics to the group), and the compression test. It won't tell you which possible path is leaking, but will confirm that you have a leak or leaks that require the engine to be disassembled for inspection/repair/replace. If no leaks then we go a different direction.

I previously suggested a leakdown test, but that's only after a compression test indentifies that you have a leak. It also requires a potentially expensive tool, and also requires compressed air. It's handy info but not really applicable if you don't have good compression. You'll have the engine out and the heads off, and will be able to easily ID the failures. So no need for leakdown testing at this point.

Cleaning grounds is a fun task, but not critical to the problems at hand. If the engine fails compression test, decide a path forward or back before you invest any more time or money in the car.


My recommendation anyway. So plugs out, with pictures. Then compression test, with results.

LazerSquid 09-03-2013 03:32 PM

10 Attachment(s)
Spark plugs are pulled, compression results coming in a second.

Attachment 758586



Attachment 758587



Attachment 758588



Attachment 758589



Attachment 758590



Attachment 758591



Attachment 758592



Attachment 758593

Those are starting from passenger side, back of motor, moving forward then front of motor on driver side. I also found this in the air intake

Attachment 758594



Attachment 758595

I'll post compressions in a few minutes, until then, what do these pictures say to you?

If it ain't broke, I'll fix it 'til it is

LazerSquid 09-03-2013 03:36 PM

1 Attachment(s)
Just found this on the threads of my compression tester after testing one of the cylinders.. Not as optimistic anymore

Attachment 758596



If it ain't broke, I'll fix it 'til it is

LazerSquid 09-03-2013 03:45 PM

8 Attachment(s)
Drivers side compressions


Attachment 758597



Attachment 758598



Attachment 758599



Attachment 758600


Passenger side compressions



Attachment 758607



Attachment 758608



Attachment 758609



Attachment 758610



If it ain't broke, I'll fix it 'til it is

Mrmerlin 09-03-2013 03:54 PM

the plug that has a bronze coating has coolant in the cylinder. picture 5,
NOTE the first two pictures dont show the tip in the sun that makes it hard to read.

the compressions are low should be about 145 to 170
BUT they are all close so if the gauge is leaking a bit then the numbers will all be low,

LazerSquid 09-03-2013 03:58 PM

mrmerlin, I uploaded the passenger side compressions, and they are all 145-155 range. also, the two middle cylinders on the drivers side were both spraying coolant out when I was turning the engine over, so I suppose that's pretty definitive; Drivers side blown, passenger side fine.

Leon Speed 09-03-2013 04:29 PM

Plugs 5 to 8 definitely look washed. The low compression numbers are consistent. Too bad, let's hope it is just the head gasket.

Mrmerlin 09-03-2013 04:29 PM

OK well you know where the coolant is.

So spray about a 30 second spray into both of the coolant filled cylinders and turn the engine over slowly by hand,
this to displace the coolant so the rings dont rust.


you will need to pull both heads as replacing only one HG is a sure fire failure waiting to happen

Imo000 09-03-2013 04:32 PM

Was the throttle blade open during the compression testing? Also, are you sure it was coolant and not fuel vapour coming out of those two cylinders.


All times are GMT -3. The time now is 09:28 PM.


© 2024 MH Sub I, LLC dba Internet Brands