Coolant Overflow/Bubbling - Blown Head Gasket??

Volvolian · Post by **Volvolian** » 16 Apr 2016, 19:09

My coolant reservoir is overflowing and bubbling when the engine gets hot, I checked the lid, plastic and tubing for cracks - there is a small crack in the plastic that the tubing grasps and could be a pressure leak. Is there a test I can do to see if it's the head gasket? I understand this is an expensive repair to do. The oil doesn't seem to have any coolant in it - no green coloration or milky texture.

Post by **kahl** » 16 Apr 2016, 19:27

Get a new overflow bottle. Fill and burp the system and monitor your coolant level. I would also do a compression test on all five cylinders and hopefully all will be within 5 lbs of each other.

Post by **precopster** » 16 Apr 2016, 19:39

Exhaust gases check via colored liquid. The kit is costly however the liquid supplied can be reused many times if re-oxygenated with the supplied hand bulb. The compression could have varied by 5 psi before the problems so this is inconclusive.

Post by **kahl** » 16 Apr 2016, 20:06

The key word "hopefully" all five clylinders will be with 5 lbs. A leaking head gasket will result in one or more cylinders substantially lower than the others. Thinking of the five V-70s we have in the family I would guess the average compression is about 155 to 160 lbs. A compression test is cheap, quick and easy.

Post by **kahl** » 16 Apr 2016, 20:22

I also want to point out that Mike's statement that low compression on one or several cylinders pointing to a failed head gasket is valid. It is inconclusive that low compression points directly to a failed head gasket. Hopefully all your compression is close on all five cylinders telling you your head gasket is ok.

bugs11 · Post by **bugs11** » 16 Apr 2016, 20:41

Do an exhaust gases in coolant test. My local Or'Reillys rents the kit for $20 or $30, but you have to buy the diagnostic liquid separately. Lucky for me I have a neighbor who is a mechanic and he just brought his shops kit home and tested mine - it was a blown head gasket. Coolant was boiling out the reservoir, only way I could drive it was with the heater on full bore and short trips at that. And then replacing the head gasket began my journey into working on an 850.

Post by **abscate** » 17 Apr 2016, 04:14

Do the simple things first, replace the reservoir. Unless you overheated it, no reason to think loss of pressure from crack isn't the root cause at this moment.