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Well, just pulled my oil cap to add some oil (it's been burning a lot) and saw the dreaded milkshake on the bottom of the cap. I rebuilt the engine ('87 16v) about a year ago and it has 7000 miles on it now. The coolant tank has lost a small amount of coolant.
Could the new head gasket be bad? Would that explain why it's been burning oil? I wouldn't think so. Maybe the cooler O rings? Any thoughts?
Thanks,
-Mike
Like the others have said, check the actual oil. While my 944's cap and fill tube have always been clean, I've seen stuff like that on my other cars which stressed me out until I drained the oil and saw that all was good.
I had that for so long -- like a couple years -- that I figured it was normal. Then, it suddenly got worse:
I pulled the oil thermostat housing and the o-rings where clearly worn out. Since then, I haven't seen one iota of this stuff in the cap, and there's been plenty of short trips in cold weather.
Don't buy it: this is a sign of deteriorating seals somewhere, most likely the oil thermostat (or cooler if NA). If you suspect tney are old or original, 100% they are starting to fail. Not a crazy hard job to replace either. Just do it
Prudent to pull the oil/water cooler and replace the seals, or at least inspect it.
If you get coolant in the oil, Porsche recommends replacing the rod bearings (factory service manual). If you catch a bad seal this early then you have side-stepped the rod bearings.
I guess it'll be prudent to check all the seals. Is there a way to see if the head gasket is leaking without pulling the head? It'd be a shame if any of them were bad since every seal in the engine is brand new.
Is there a way to see if the head gasket is leaking without pulling the head?
Good luck with that one. I had the same question. From our local auto parts chain, I borrowed the tool to use the liquid (had to buy the liquid) where you seal it on top of the coolant reservoir and its supposed to turn colour if HG is leaking. Mine passed that test no problem. There were no other indications. In fact, when I pulled the HG, it didn't appear to be leaking; no holes, just some discoloured spots.
But, after changing it, my emissions test went from bad fail to better-than-ever. Granted, I also took the head to the machine shop, but the Drunk Machinist basically just replaced the valve seals--which weren't bad really--and cleaned it all up. I don't think there is an easy way to tell if HG is leaking. But if you've only got 7000k on a rebuilt engine, I highly doubt your HG is leaking (unless you're running some crazy boost psi).
Did you replace the oil cooler housing o-rings on rebuild? There's two of them, and one is sometimes not replaced correctly or missed. That, and the fit may be off. Scroll down to step 13 on this excellent write-up and read the entire second paragraph: https://members.rennlist.com/tom8695..._seal_repl.htm
Yes, the oil cooler seals were replaced, and I'm very confident they were done correctly, as it's not my first time. But it can't hurt to check them. I don't have power steering anymore so they're quite easy to get at.
Have you been warming the engine up completely the last few trips?
That is, getting the coolant and the oil up to full temp?
Keep in mind that there is a lot of water produced in the combustion process, and some of it ends up in the crankcase.
If you don't warm the engine up all the way and boil off that water, it can end up looking exactly like that.
What does the oil look like on the dipstick? What does the coolant look like?
Joe, I used to think the same, but since I've changed my seals, not a hint of that stuff--and it's pretty cold out now with plenty of short trips! That, and when the situation got real bad, not a hint of it on my dipstick or in the oil after draining. I'm not kidding.
But there's an easy way to test: wipe the cap & drive on the highway for 30 mins. If returns, no way it's condensation
From our local auto parts chain, I borrowed the tool to use the liquid (had to buy the liquid) where you seal it on top of the coolant reservoir and its supposed to turn colour if HG is leaking. Mine passed that test no problem. There were no other indications. In fact, when I pulled the HG, it didn't appear to be leaking; no holes, just some discoloured spots.
I use the block test fluid hundreds of times a year in our shop, and it's about 80% accurate in my estimate. It will trigger at about 30PPM of carbon monoxide, and the test must be done properly for it to have any type of usefulness. On vehicles like ours with a pressurized surge tank, it must go through a warm up cycle to move coolant from the engine through the radiator and tank.
A light amount of condensate on the cap or upper tube is normal. I agree with you on the heavy condensation in the oil fill tube as a sign that cooler seals are leaking. Head gaskets usually add contamination to the coolant (making it dirty or look rusty, and it will smell acrid, not sweet). If coolant stays clean but slowly goes down in level, it's likely cooler seals.
10-21-2018, 03:13 PM
Milkshake in oil cap
