Hey guys, have anyone of you ever used one of these? http://www.autozone.com/autozone/cat...&brandName=OEM

Basically, what you do is suck some coolant into it and if the dye changes color, it tells you there are exhaust gasses in it and you have a blown head gasket. Reason I am wanting to test this is I just rebuilt my motor and now it is backfiring out of the exhaust, but only every 15 seconds or so. The heads came off my old motor and one was hit by a piston I replaced the intake valve on it, but not the exhaust. It backfires on that cylinder now (checked it with a temp gun and it is lower then the rest by at least 50* while warming up), but otherwise runs okay. I don't want to let it run to long if it is a head gasket or bent valve and figure this is a good way to check. If it fails the block test, then I have to get the head resurface, if it comes out good, then I will pull he head and replace the exhaust valve, ugh...

Thanks,
Bill

 

They are a great tool for finding leaking head gaskets, the one I used you didn't suck coolant into it, you took of the radiator cap and hold the tester in the radiator with the engine running and the liquid in it changes colors if the are hydrocarbons present.

 

Okay, maybe I miss-understood the directions, but same thing... Thanks for the reply for $30 I think I will pick it up, answer my questions for good. How long did you have to hold it over the radiator to get a reading and did the car have to be warmed up?

Thanks,
Bill

 

Double post FTL...

 

Yep thats all it is and it will change to a greenish,yellow tint if its blown. Do you see coolant pouring out of the exhaust at all??

 

Nope, I really don't think its the head gasket, I believe it is a bent exhaust valve. But for $30 I would rather be safe then sorry and know for sure what is causing it. I haven't let it run much and I don't seem to be losing coolant, only topped it off, but I think that was from bleeding the system.

I will let you guys know how it works out.

Bill