My 2002 Mazda B2300 emits bubbles into the coolant overflow tank even after...

B

Bob

New member
...the t'stat is open. Normal? I'm trying to troubleshoot the problem that when the engine is hot and under load (going over mountain passes) it stalls and loses power, as if it's vapor locking. When in neutral the engine revs fine. Around town it also runs fine. Mechanics have replaced the fuel pump, air mass flow sensor, and fuel filter - all to no avail.
 
have you had a compression check,what you're describing sounds like a blown gasket or cracked head. vapor lock is a thing of the past,unless you own a carbed vehicle. do a proper check and find out what is going on in the chamber. to do this, take a compression gauge and take a "dry" reading, then put about a table spoon of oil and put it in the cylinder just before you do a second "wet" test. the first check will tell you the actual compression, the second will isolate whether it's valves or rings.from high to low there should only be a 10% difference, ideally. ideally being the key operating phrase.
 
If you fill up the expansion tank on the radiator and warm the engine
and just let it "idle".....................

If bubbles appear in the water it indicates a leaking cylinder
head gasket.
 
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