Head gasket leak?

theprep · Post by **theprep** » 02 Jan 2012, 20:03

My 1996 850 started to consume coolant a few weeks back, with no apparent trace as to where it was going. I filled it back up to see if I could trace the issue, in the meanwhile, I did notice a light coolant odor periodically when the heat was on sometimes what I believe are drops of coolant in the driveway. I finally figured it must be the gasket or a crack in the block. Vehicle has approximately 180K, never over heated. I added some Bar sealant, changed oil and plugs today. While under the car, I did notice some coolant on the undercarriage, around the lower control arm, passenger side. Thinking the gasket may be leaking on the backside of the engine. Other than a compression test, suggest any other procedures to track this issue down? I rather not spend a ton of money as this is just a back up vehicle to augment my motorcycle.

Post by **jblackburn** » 02 Jan 2012, 20:17

Based on that location, it actually sounds more like your water pump or something is leaking. I'd remove the timing belt cover and have a look.

theprep · Post by **theprep** » 02 Jan 2012, 20:26

Neglected to mention there is evidence of coolant in the oil. The dip stick tube is rusted, oil on the stick was milky/frothy. When changing the oil, I did notice some foam. Oil still had a petroleum texture, but again, I did notice a small amount of foam. Seems to consume coolant out of the reservoir about every two weeks.

Post by **jblackburn** » 02 Jan 2012, 20:39

At this point I would run either a compression test or a combustion gases test in the coolant.

Do you see little bubbles in the coolant reservoir if you run it with the cap off?

theprep · Post by **theprep** » 02 Jan 2012, 20:42

I didn't check, but will in the morning. What will that tell me? Thanks for the suggestion

Post by **jblackburn** » 02 Jan 2012, 21:57

Low compression numbers will tell you if there's a small leak in the head gasket between 2 cylinders (usually 2&3 for some reason); combustion gases test will tell you if there's a small leak showing up in the coolant reservoir. The test kit will turn a different color if it detects hydrocarbons in the coolant.

theprep · Post by **theprep** » 05 Jan 2012, 19:39

haven't had a chance to run the test, but I did notice this morning there was a small puddle under the car, passenger side, lower control arm area I mentioned before. Again, I have detected coolant in the oil prior to the change on Sunday. Suppose I will know more once I do the two test mentioned above.

Post by **jblackburn** » 05 Jan 2012, 20:11

That location still says water pump. Or coolant reservoir leaking.

Did you just find moisture on the oil dipstick or cap? Is there oil showing up in the coolant?

Post by **kickin_it** » 05 Jan 2012, 21:19

I was having similar issues with my motor, unfortunately my ended up being very bad and I had to rebuild. I agree with JBlack, the location sounds like water pump leak. Pull the timing cover off, start the car and watch around the water pump especially near the weep hole to see if possibly the gasket has failed. You can always check to see if exhaust is present in the coolant with additives you can pick up at a parts store, this would let you know that coolant and exhaust are mixing somewhere. I assumed the worst and opted for a compression check which only confirmed that my head gasket had failed. Compression check is as easy as changing a spark plug and many of the parts store have loan-a-tools which include everything needed to test. Best of luck, lets hope its just water pump which isn't too bad of a job, keep you nice and busy on a Saturday.

SimLyons · Post by **SimLyons** » 05 Jan 2012, 21:41

You might do (add) a cooling system pressure test. Again, a lot of the parts stores loan out these tools. The tester just goes on your reservoir where the cap is normally and the you pump it up to whatever is in the spec for your year. Probably around 15psi. See if it holds the pressure. While you are waiting for a pressure drop, look around (water pump? Clean off all around it first or you might not see a very small leak). This will pressurize your entire system, as if the car is running. So, don't run the engine and you can feel around the bottom of the water pump for wetness. Also look around all the hose connections.