Can't purge coolant, radiator slowly overflows even when thermostat is closed.

[The_Eric]

Originally Posted by mattd
Originally Posted by Trav
Originally Posted by mattd
FWIW those "block" testers are completely useless IME.

Have you tested your cap?


I have to disagree with that. I used one on an engine with a very minor crack in the head next to the intake valve and it turned the fluid yellow in seconds.
The fluid does react quickly to hydrocarbons, granted it will not detect a internal leak into the oil or an external one but that does not render the tool "useless".
I think of it as just another testing tool in the arsenal.


I have had several engines with badly blown head gaskets and it has never changed color. I can probably say it worked on 1 vehicle that coolant was boiling out of the reservoir. I find the best tool for this is a 5 gas analyzer. Heck I have even stuck the tester near a tail pipe of a running car (for testing purposes) and was reluctant to change color. Again, just my experience with this particular tool.

I'm on the fence about them. I'd say ime they're right about 50% of the time.

I tell customers that if it "passes" you're not necessarily out of the woods, but if it fails, you're definitely done.

 

[Trav]

The reason people don't think they work is it can only test for one of the basic conditions possibly caused by a failed head gasket, hydrocarbons in the cooling system, that is all.
Head gasket fails could also include..

Oil passage to cylinder (not common)
Coolant passage to cylinder
Cylinder to cylinder
Coolant to oil passage
External leak due to a failed gasket or loss of tension on the head due to head bolt thread pull out.

Another cause for hydrocarbons to be present in the cooling system is from crack(s) in the head, this is more common with some engines than others especially near the valve seat area and between valve seats.
A pressure test and leak down test are also used to diagnose failure as well as looking for coolant in the oil and external leaks.

 

[Twisted1]

Is the heater hose easy to remove?

Yes very easy to remove