Oil In Coolant

tbenedict · June 13, 2008

Hello,

I have a 98 K1500 Z71 with a Vortec 350. Recently I found oil in my coolant overflow (very dark and felt like oil). My coolant is now brown and soupy. I have not noticed any bubbles on the oil dipstick and it does not appear low on oil. I went to clean the overflow tank and noticed the supply line was stopped up. The truck had not been run in several days, but the system must have held some pressure until I removed the stoppage....

I have heard this can be the head gasket(s), but I am wondering if it could be the oil cooler or tranny cooler leaking.

Anyone have experience in this situation?

If it is a head gasket, are there any special tools needed? I read a procedure that recommended a torque angle meter to tighten the head bolts, but all I have is a torque wrench.

Thanks for the help.

bossier62guy · June 13, 2008

Hello,

I have a 98 K1500 Z71 with a Vortec 350. Recently I found oil in my coolant overflow (very dark and felt like oil). My coolant is now brown and soupy. I have not noticed any bubbles on the oil dipstick and it does not appear low on oil. I went to clean the overflow tank and noticed the supply line was stopped up. The truck had not been run in several days, but the system must have held some pressure until I removed the stoppage....

I have heard this can be the head gasket(s), but I am wondering if it could be the oil cooler or tranny cooler leaking.

Anyone have experience in this situation?

If it is a head gasket, are there any special tools needed? I read a procedure that recommended a torque angle meter to tighten the head bolts, but all I have is a torque wrench.

Thanks for the help.

It could also be a leaking intake gasket. You might want to do a compression test on the engine prior to removing the head. If you do have a bad head gasket a torque wrench that covers the proper range will work just fine.

Zembonez · June 13, 2008

I'd confirm that it is actually oil first. Old coolant can get really nasty looking... especially if it hasn't ever been changed or not changed for a long time. Either could be possible on a 10 year old truck. If it is indeed oil in the water, it will eventually end up with water in the oil. A breech in the two systems will allow water to enter once a hot engine is turned off and the water is under pressure.

tbenedict · June 13, 2008

I'd confirm that it is actually oil first. Old coolant can get really nasty looking... especially if it hasn't ever been changed or not changed for a long time. Either could be possible on a 10 year old truck. If it is indeed oil in the water, it will eventually end up with water in the oil. A breech in the two systems will allow water to enter once a hot engine is turned off and the water is under pressure.

I flushed the system to get that dexcool out when I replaced the water pump a couple of years ago. It got a little congealed a little while later and I had Free Service flush it again.

What I took out of the overflow was quite black and felt just like oil (even smelled like it). I wasn't going to give it a taste test .

I'll have to crawl under it this weekend and do a little tracing.

Zembonez · June 13, 2008

I flushed the system to get that dexcool out when I replaced the water pump a couple of years ago. It got a little congealed a little while later and I had Free Service flush it again.

What I took out of the overflow was quite black and felt just like oil (even smelled like it). I wasn't going to give it a taste test .

I'll have to crawl under it this weekend and do a little tracing.

Not a good sign but probably quite fixable at this point if you don't let it go too long. Good luck.

jrbean · June 13, 2008

Sounds more like an oil cooler in the radiator. Check your trans fluid level. The intake gskt and head gskt usually dump coolant into the oil when they go.

Zembonez · June 13, 2008

Sounds more like an oil cooler in the radiator. Check your trans fluid level. The intake gskt and head gskt usually dump coolant into the oil when they go.

Good point. This is why I'd recommend checking thoroughly before deciding to "fix" something.

pennzoil29 · June 14, 2008

Sounds more like an oil cooler in the radiator. Check your trans fluid level. The intake gskt and head gskt usually dump coolant into the oil when they go.

+1 on this one.

tbenedict · June 14, 2008

Sounds more like an oil cooler in the radiator. Check your trans fluid level. The intake gskt and head gskt usually dump coolant into the oil when they go.

+1 on this one.

I'm going to check, but is tranny cooler connected to the radiator? I have had an issue losing tranny fluid, but thought it was leaking into the transfer case. Haven't confirmed that yet though.