joecitizennn

Is it possible for a leaking turbo to contaminate the coolant system with oil? I have oil showing up in the coolant on my 86 951 and it does not smell like a blown head, and I do not have any overheating issues. I am just wondering if there is any other place in the engine where the oil and contaminate the coolant.

there is no coolant getting in the oil.

Rip It

I would say no. There is no connection of oil and water in the turbo. The turbo is only water cooled.

Darwantae951

The turbo is water and oil cooled, as well as oil lubricated. I don't know what the inside of the CHRA on a stock turbo is like, so I can't answer weather or not oil and water can mix.

joecitizennn

Well what kind of boost levels will blow a head gasket? I have had this car only a week and soon noticed the boost was set high at 17 psi. On occasion a spike would nearly hit 20. I have reduced boost to 13 psi. The wastegate is stock, I was unsure if it would be possible blow a head gasket with a stock wastegate.

I bought this car understanding that the headgasket needed to be replaced but I am still not convinced totally.

je951

I had the same problem here recently, but my coolant was contaminating the oil,turned out to be a head gasket. It's either the turbo, which could need a rebuild,or possibly the oil cooler.

je951

And anything over 15 psi is to much for the stock motor (if you want it to last that is). The factory cycling valve(which you obviously don't have) cuts of fuel supply at 12.5 psi,so 13 is straight for everyday driving.

joecitizennn

Isn't the oil cooler on the 951 an air/oil cooler, not a water/oil type?

je951

it's a water/oil type.

je951

theres o rings inside it that prevent them from mixing, their probably worn out.

joecitizennn

How easy are they to change?

je951

Much easier then a head gasket haha,but still pretty time consuming. But theres a kit out there that comes with the o rings and gasket that should fix your problem.

joecitizennn

so, you are saying that the turbo can possibly allow oil into the coolant?


also, how much boost can a 951 head gasket safely take?

JohnKoaWood

No the turbo cannot allow oil to mix with coolant... they are separate passages in the turbo center section. unless you cracked the turbo center section (not impossible, but MANY other issues would be present)

It is either your oil cooler / filter housing or head gasket... could be a cracked head, but this is the least likely!

Tom M'Guinn

17-20psi is plenty to blow the head gasket. Yes. it is easy to blow the gasket with the stock wastegate. There is no particular smell to diagnose a blown head gasket.

Oil mixing in the coolant could be a bad head gasket, but more often than not it is the caused by the oil thermostat housing seals, especially if you have no other head gasket symptoms (like overflowing coolant, lumpy idle on start up, etc.).

Read the first part of this write-up, with tips to determine if you have a bad head gasket.

http://members.rennlist.com/tom86951/headgasket.htm

If it's not the head gasket, then see this write up to see how the oil thermostat housing seals are replaced.

http://members.rennlist.com/tom86951..._seal_repl.htm

joecitizennn

ok, that was informative, but I wonder if I have a couple seperate problems.

my symptoms are as follows,
Oil showing up in coolant.
No coolant showing up in oil.
Car runs hot on occasion, usually at slower driving and idle.
Thermo-fan switch does NOT kick fans on when heat rises.
I am not loosing coolant in my overflow tank. The level stays the same.
All spark plugs are the same color.

If I get the time I will run a leakdown check of all cylinders tomorrow, but I wonder if the running hot issue may simply be a bad fan thermostat, and the oil issue is OPRV housing seals.