Engine Coolant Question

This sounds similar to what my truck does. I haven’t had any official tests done but just chock it up to a head gasket.

In my truck, after driving for awhile on the highway under load, the cooling system will push coolant out into the overflow tank. Eventually, it’ll fill up and start over flowing down onto my skid plate.

What I found is this. If the engine is barely working hard, it barely spits coolant out. I have a system down to where I’ll drive in 4th gear (manual) at 3k rpm 65 mph. Engine is barely working to maintain speed, I don’t lose much coolant, and I get 15mpg.

If I drop it into 5th gear, I can watch my engine load increase, and the overflow fills a lot faster.

The bubbles you’re seeing aren’t from the drain plug. If you look closely, you’ll notice that the rubber hose running from the radiator to the overflow, there’s an internal plastic tube running all the way to the bottom of the overflow tank.


What I’ve learned in my research is that these head gaskets commonly leak st cylinder 6, and let exhaust gases into the cooling system. My theory is the cooling system gets too pressurized, so the radiator cap opens up and allows coolant to start slowly flowing into the overflow.

Anyways this is all over the place and sorta rambling and I hope it made a bit of sense. For now my solution is to just transfer the coolant from the overflow back into the radiator manually, and drive like a grandma. And carry extra coolant on long trips.

If you do notice yourself starting to overheat, crank the heater on full blast, pop your truck in N, and rev it up to 3k rpm. This will get air flowing across the radiator and cool it down.

 

If you have a blown head gasket, that is a $3000 repair at most dealers. Drain the system COMPLETELY and try Steel Seal head gasket repair. It will cost you about $100 for two containers, but it is worth a shot. It is not compatible with Toyota coolant so that is why you need a complete flush and fill with pure water to use the stuff. If it works, they refill with Toyota coolant.
Do a search to find out more.

 

I had an exhaust gas test done and it came back negative.

 

The best way to test for a HG leak is a leak down test. Compressed air gets pumped into the cylinders and depending how quick the pressure drops, can indicate various things. If you want a definitive answer that’s what I’d have done.

I haven’t yet because mine isn’t too much of an issue for me yet.

 

I'm still good with just the replaced rad cap. Fluid levels are stable and temp doesn't go above half on the temp gauge.

 

Dead toad? What, were they out of eye of newt?....

 

why you have dead critters chillin on your dash

 

Because leaving live critters in your car is highly frowned upon in Phoenix in the summer time!

 

Assuming my cooling problem is a bad head gasket....

As the motor will be apart....

Is there anything I should consider replacing?
Like fuel injectors, timing chain, or other sorts of things.

As I dont have enough time (or confidence) to do the job myself it likely will be a stealership doing the HG repair.