Losing heat

I have a lot of fleet vehicles that I work on. Anti freeze usage gets ridiculous sometimes. The most overlooked part of the cooling system is the pressure cap. If it won't hold proper pressure the antifreeze will get pushed out. I know it sounds to simple or the cap was replaced with the radiator. Quality control.......... If you have checked for the usual leaks and found no evidence of anti…

Anytime the customer says that the temperature gauge fluctuates tells me that the engine might of overheated in the past. Have you done a block check yet? I would do one with the engine cold and hot.

Would you use a chemical checker, or is there a better way?

If you have a gas analyzer check for hydrocarbons in cooling system if present suspect damage to the block, cylinder head, and cylinder head gasket . The “air in system could be exhaust gases”

My landlord still has a functioning dyno so I'll be asking to use the 5 gas analyzer tomorrow.

I wish I had a gas analyzer, but my state doesn't have an emissions program yet and I haven't been able to justify one. Thank you for the suggestion, though. I might have to squeeze one out of the budget soon!

Hook a cooling system pressure up and see if pressure gos up rapidly while running . Works every time

That is a fantastic idea, Randy.

How fast would it rise if there were an issue?

You would see a rise pretty quick not a lot butt I have seen as little as 7psi in a very short time . Just my testing

Michael; Good evening Sir I hope this message finds you doing well. If you have an inspection camera you can remove the spark plugs and look for the "Clean Cylinder". Usually with an engine that has a slow leak one or more cylinders will have clean piston tops and/or clean cylinder domes. Sometimes with a pressure tester attached to the radiator you can even see antifreeze running down the…

Do you have a scope and a pulse sensor?

4425 and a WPS500 👍

Yes you can use a scope butt quicker my way . If you want to use scope check out super mario on y tube he did this a few months ago

Literally watching right now

Do you subscribe to him ?? If not do he is pretty damn good

Yep, I do

I forgot about that video, thank you for mentioning it.

The WPS500 is a pressure transducer but not a pulse sensor. A pulse sensor is much more sensitive than a pressure transducer. It doesn’t measure pressure or vacuum directly, but measures a change in state. It is extremely sensitive. It is similar to a knock sensor. If you attach a pulse sensor to the cooling system it should be obvious if you are getting compression spikes in the cooling system.

You can make the WPS act just like a pulse sensor.

If you can't find an external coolant leak with pressure and suspect a H/G just warm it up at the end of the day. Let sit and cool and with first start in the morning if it has a misfire that goes away in a minute or two you may have confirmed a head gasket. Check misfire code and pull that plug to see washed cylinder. HTH

All great ideas, guys. Thank you!

Along with all that has been suggested, our new go to tool for head gasket leaks is the ATS Bullseye tester

Already mentioned but if no visible leaks, chemical checker, look into cylinders for a clean piston top. I've also had good luck using a gas analyzer to sniff the coolant. It will pick up the HCs. One of the reasons I never parted with my old Allen big box analyzer w/ 2-gas. Just don't let the analyzer suck in any coolant.

I have had success by bringing each cylinder up on TDC and pressurizing the cylinder with the radiator cap or degas bottle cap off and watching for bubbles. I know this is time consuming and next to impossible with some engines but if you have a suspected cylinder that is de-carboned or cleaner than the others by viewing with an inspection camera it may be worth the verification.

That's my go to. Never lies.

Hey Mike, Have an update on this one for us?

Nelson, since then the customer has parted ways with this vehicle.