"Check Engine light" flashes when going down a steep hill

[Phil V]

I'm afraid you might be right Cruiser... But I've been thinking that for years now...

I have foam under the oil filler cap, and it's been like that for years, but the oil on the dipstick looks fine.

A lot of people say that the foam on the filler cap is normal... "It's just condensation", and stuff like that.

But when I look at that pic of the plugs in the post above, the color makes me think there might be something going on there between the #2 and #3 cylinders. They're right next to each other..

I'll have to check with the local parts stores about that test kit, I wonder what I'll find in the radiator...

Jim, if you think it might be a faulty head gasket then do a cylinder leak down test. Or you could use an adapter that screws into the spark plug hole and the other end of the adapter to an air hose. Plug the thing into the air hose with at least 90psi and take your radiator cap off. if the head gasket is bad then you will see air bubbling through the anti freeze in the radiator.

You can get a regular cylinder leak down test kit from Horrible Freight pretty cheap. https://www.harborfreight.com/cylind...ter-62595.html I bought one of those kits and it works like it's supposed to.

[Jim2]

Thanks for the suggestions you guys.. It looks like the leak down testing kit and the "Block tester" cost about the same.

But my truck doesn't have a radiator cap, so I wonder how those tests would work at the overflow tank?

[07cruiser]

Good question, I'm not sure. So what I would do is like Phil V said is to do a leak down test. You'll either see bubbles in the overflow or you'll hear it coming out of the exhaust or even the intake.

[roadiestar]

One way to check for head gasket leak .Is to take the cap off the rad start engine let run to its warmed up. Once warm look in the rad and see if there is any air bubbles coming up. If you see any you have a bad head gasket.