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About 2 months ago I was looking at my fluids and noted some dried up pink antifreeze on the coolant reservoir. The cap was an original, and it appeared to have been deteriorating because there was gunk on the top. I replaced it and moved on.
Fast forward to about a month ago, some antifreeze was seen around the water pump (a tiny amount, see picture) when the car was up getting the spark plugs. No drop in coolant fluid, no overheat, no noise, no CEL. My mechanic said keep an eye on it, that the pump was probably starting to fail, but could wait a bit.
Ive been monitoring it closely with no drops noted under the car and no dip in the fluid level. My problem is, I pulled the cap off the coolant to check the level (because my reservoir is opaque) and noted the same sludge I saw on the original cap. A picture of my coolant is shown.
Oil was changed about 1000 miles ago and appeared normal.
The car: 1999 996 tiptronic. 211,000 miles! engine rebuilt around 170. No oil leak, runs fantastic. oil pressure gauge acts as it should while driving, temp sits around 190 when warm. The dip stick is clean.
So of course I'm worried this is motor oil signifying a blown head gasket but I would have expected something more ominous to happen- especially since in hindsight the original cap that I replaced in late July or August had the same stuff on it. What else could this be?
My plan was to flush the coolant and change the water pump
* Have you been taking a lot of short drives? could be the cause of the "sludge" under the cap (how does your oil fill cap/tube look like?)
* Coolant around WP: likely due to a crack in your reservoir. Have a pressure test done of your cooling system to locate the source/cause. NOTE: WP or tank crapping out while driving is not good
Looks like oil sludge on the coolant cap. Any details of the engine rebuild (cracked heads)? I wonder if it's residual coolant oil intermix from previous engine failure.
I think it's a good idea to flush out all the coolant and keep monitoring it.
Wow... from the looks of the first image, it appears the coolant coagulated. Looks like jellied cranberry sauce. Is that dexcool or did someone get the bright idea to pour Pepto Bismol into the system?
The water pump is shot unless as kromdom noted the coolant tank is leaking.
If the water pump is the source of the leak it will have anti-freeze stain/residue on the water pump housing behind/under the pulley.
If you decide to replace the water pump replace the T-stat too.
Regardless of what you replace I think a drain, flush with regular water, then a refill with fresh Porsche anti-freeze and distilled water is called for.
When you drain the old coolant catch it in a *clean* drain pan with absolutely no oil. Clean the drain pan before hand with a non-residue cleaner. I use cans of aerosol brake cleaner.
Let the coolant sit a while. If any oil globules appear on top of the coolant there's an intermix problem.
It doesn't look like an intermix problem to me though. It looks like the wrong anti-freeze was used or two incompatible types were used.
You are right. I didn't look hard enough and thought that was the underside of the oil filler tube cap. Obviously -- with both eyes open -- that's the coolant cap.
There should be nothing on it but water/anti-freeze.
Thanks for everyone's thoughts. A few updates:
-checked the oil cap. looked normal.
-the debris on the cap is defintely oil as many have said
- i siphoned off the top 12 ounces or so of coolant out of the tank so I could take a better look. It was opaque, but pink. I let it sit for a few hours then assessed it. The smallest tiny film of shine over the top showed some trace oils in it, but nothing else and no sediment (See pics).
I am wondering if this small amount of oil predates me. Like I mentioned, I noticed it first about 3 months ago and have driven the car about a thousand miles since then because I thought it was just breakdown of the original coolant overflow reservoir cap. There is a small amount of old oil in that reservoir that I just cannot get to to remove it.
The small amount of antifreeze is still present around the water pump edges. No such leak is seen around the reservoir, and I have added no coolant to the basin since I bought the car 6 months ago. When I bought the car the center radiator had a leak found on PPI and that was replaced.
My plan, as of now, is to replace the water pump and thermostat, flush the coolant line, and refill with new coolant. Then, pray. thoughts?
COMPRESSION TEST.....to locate the cause/source of the oil in coolant. Above plan (i.e. expenses) will not do so.
Neither of those tests will likely show anything... That's why this issue fools so many people who are not specifically experienced with the M96.
The intermix generally comes from outside the combustion chamber.... Inside the cylinder head oil and coolant capillaries.
This case appears to have just started. He is super lucky to get an early onset symptom before collateral damage has occurred.
Why does this collect in the bottom of the coolant cap first? Because the cap has a built in pressure balancing device that bleeds some coolant past it at high system pressures. The intermixed oil and coolant is very light and suspends easily, going straight to that cap first before anywhere else.
This is a super early diagnosis, kudos to the owner. Now he just has to take this seriously assume the worst and hope for the best while finding the right person to save it.
This obviously raises some questions... Since you mentioned a PPI, should we assume that the reservoir didn't look like this when it was done? If it did (but to a lesser degree), it's possible that there was a failure before your purchase, that was repaired, but the cooling system wasn't totally cleaned out and what you're seeing now is the residual oil that was/is coating the internals of the system. This could be good on one hand (the head or cylinder crack has been repaired) but bad on the other (all the hoses in your cooling system may be damaged and ready to fail due to oil in the system). The other scenario (potentially much worse) is that there's a very fine crack somewhere (head or cylinder wall) that could let loose at any time - seeing as you've been driving it like this for the past three months, this seems less likely to me - but you never know... I wish you luck, and hope it's the lesser of potential disasters
This obviously raises some questions... Since you mentioned a PPI, should we assume that the reservoir didn't look like this when it was done? If it did (but to a lesser degree), it's possible that there was a failure before your purchase, that was repaired, but the cooling system wasn't totally cleaned out and what you're seeing now is the residual oil that was/is coating the internals of the system. This could be good on one hand (the head or cylinder crack has been repaired) but bad on the other (all the hoses in your cooling system may be damaged and ready to fail due to oil in the system). The other scenario (potentially much worse) is that there's a very fine crack somewhere (head or cylinder wall) that could let loose at any time - seeing as you've been driving it like this for the past three months, this seems less likely to me - but you never know... I wish you luck, and hope it's the lesser of potential disasters
Good point about this being possibly residual after a prior repair.. Unfortunately thinking like this isn't what saves an engine.
Last night I was going through scenarios I've experienced first hand like this... One came to mind where an expansion plug was leaking in one cylinder head that never got any worse for years and always looked just like this coolant cap.. Then all of a sudden the flood waters opened up and filled the engine with almost all the coolant from the cooling system.... That plug finally let go. This is an easy fix IF this is occurring now.
That said, what id do is an oil service and. Used oil analysis... The results will come back with percentage of water and percentage of potassium, and glycol. This will tell the real story. Buy the oil from www.rndeuroparts.com and select the free oil analysis at check out. Don't use freakin Blackstone!
10-24-2016, 02:32 AM
Badness in the coolant tank
