850 Turbo blown head gasket?

stanley_changuion · Post by **stanley_changuion** » 29 Oct 2008, 01:58

Hi guys. I services my 850 the other day. I also changed the coolant. Since then it looses its coolant. At first I thaught I didnt do the cap up tight enough. But I have since seen it makes little bubbles into the expansion tank through the little return hose. Is it common for these to blow head gaskets? And how easy or hard is it to do a head gasket on one of these? Its a 1994 850 Turbo 2.3l. I am a digger mechanic by trade, so I know my way around engines, I just hate working on cars...
Thanks guys!

Post by **Ozark Lee** » 29 Oct 2008, 06:55

Is it common for these to blow head gaskets?

Unfortunately yes, it is a common problem. Particularly if the car has been overheated.

Before you just tear into it I would have a leakdown test done on it to verify the problem. The Haynes manual is an excellent resource if you decide to change the gasket. The head gasket kit costs a little over US $100 and then you will need a full set of head bolts that run about US $3.00 each.

The Haynes shows how to make the special tools to keep the cams aligned when you put it back together.

...Lee

Kmaniac in California USA · Post by **Kmaniac in California USA** » 29 Oct 2008, 08:00

Bubbles in the expansion tank indicates the possibility that exhaust gases are leaking into the cooling system. This could be caused by a leaking head gasket, or one or more cracks in the cylinder head, or one or more cracks in the cylinder walls.

Before you tear it down, get yourself a "Universal Block Tester" to test for exhaust fumes in the coolant. It contains instructions on how to determine which cylinder is leaking if in fact there is a leak. Also, for good measure, do a compression test to check for pressure variations between cylinders. When you pull the head, take it to a machine shop and have it inspected regardless of what you think the problem might be.

I had the same thing happen on my "turbo-equipped" car (not a Volvo) and the problem ended up being cracked exhaust valve seats on every cylinder. Check your turbo to make sure the wastegate is opening as it should. A stuck wastegate or over-boosting turbo will burn up a cylinder head real quick.

Let us know what you find and what you do.

hcritz · Post by **hcritz** » 29 Oct 2008, 13:39

Hello Stanly...
Before you assume a blown head gasket...some aeration of the water in the coolant tank is normal.
If the car hasn't run hot...I might look as some other causes before I pulled the head.
These cars do seem to have problems with leaky heater cores...I've replaced them in both my 850 and V70. My coolant loss was small but there was a detectable odor with the heat on. Some post here have had pretty substantial leaks there.
At least the heater core is an easy job!
Check the turbo coolant hoses etc. for leaks or stains that might indicate leaks there as well.
Take Care..
ED

stanley_changuion · Post by **stanley_changuion** » 30 Oct 2008, 01:43

Hi again. The coolant definately comes out of the expansion tank cap. And it looses it over about three days, enough for the warning light to come on. It never overheated, the guage always stays in the middle.

Thanks
Stan

1996 Volvo 122S B18B
1994 Volvo 850 Turbo

Post by **MadeInJapan** » 30 Oct 2008, 04:49

You could just have a leak in the expansion tank or one of the hoses under it...take it loose and have a check. Replacement of either is relatively cheap.

Japedo · Post by **Japedo** » 30 Oct 2008, 06:17

I had a blown headgasket about 2 years ago. It was caused by one of the coolant lines going to the heater core breaking. This caused the car to overheat and the head to warp. The engine wouldn't start untill the head was plained and a new head gasket installed.
If your engine is still running ok I'd check the compression in the cylinders and go from there. I can't remember the exact price but I know the gasket set was priced reasonably through FCP groton.

Japedo 94 850 turbo 470kms
01 V70 XC 121miles
95 Jeep YJ (plow truck)

wolfspiritky · Post by **wolfspiritky** » 30 Oct 2008, 06:29

If there is a leak down into a cylinder you should be able to detect the "sweet" odor of coolant in your exhaust. If you "know your way around an engine" you should know a compression check is one of the first tests to be done.

Good Luck!!

Post by **wheelsup** » 31 Oct 2008, 17:44

Ozark Lee wrote:
Is it common for these to blow head gaskets?
Unfortunately yes, it is a common problem. Particularly if the car has been overheated.

Out of curiosity is this something that I would know right away or does it manifest itself? My car overheated when it blew a radiator hose about 4 months ago and then overheated again 1 month after that due to a bad fan relay. All at low speed. So far it's been OK, coolant level is the same, no other symptoms. Just wondering if I should expect this in the future or if it were to happen it would've already?

-matt
(crossing fingers!! I hear head gasket repairs are expen$ive!)