Lower pressure coolant cap?

[markelectric]

Does anyone know of a source for a lower pressure relief coolant cap for a 2006?

I have most of the indications that have a head gasket getting ready to let go. I need the truck for my busy season and was thinking that a lower pressure relief might help save whats left of the system, while I drive it to its death.

Any Ideas?

Thanks

[DmaxMaverick]

What "indications" are you seeing?

If it's pushing out coolant, lesser pressure will just push it out sooner/quicker. There's little you can do if a cylinder is pressurizing the cooling system. Keeping it cooler by working it less and minimizing cylinder pressure (less throttle) is about all you can do short of a repair. It's gonna happen, just help it happen slower.

If it's pushing coolant into a cylinder, the only thing you can do is run it with the cap loose. Any (minimally) less pressure cap will do the same. If a head gasket is "getting ready", the minimal pressure of the cooling system adds nothing to causing it, and lessening cooling pressure will not "preserve" it. Cylinder pressures are exponentially higher.

The OEM and replacement caps are all 15 PSI. These caps fit some later (other) models with up to 20 PSI caps, but I think 15 is the lowest of the design. A search of the same cap design for other models shows 15 PSI the lowest. 13 PSI (traditional) caps are decade(s) earlier, but they won't fit. Even if it did fit, the difference in pressure isn't enough to make a difference.

[markelectric]

I had several episodes of coolant on the ground, and first thought "bad head gasket" but never had a stiff or hard hose. I could smell a hot coolant odor after using it and shutting it off.
My mechanic thought that maybe there was a leak in the valley. He checked it out and found that the coolant was coming out between the block and transmission.
Not wanting the labor charge of pulling the engine, we opted for a shot of stop leak.
After the stop leak did its job, the upper radiator hose is now somewhat stiff. No where near as hard as my 2001 was when the HG leaking.

There is also evidence of oil seeping and baking around the number 7 cylinder.

This is the time of the year that I am strapped for cash. The seasonal business is sucking money for supplies and fuel. The return on that investment is usually decent but will not receivable until October at best.

Just trying to limp it thru....Probably could just park it but that would create other scheduling problems. If it comes down to it, I will fight the schedule rather than the cash flow.

Thanks for any help.

[DmaxMaverick]

An oil leak is no indication of head gasket failure. A coolant leak as you describe is also, no indication of head gasket failure. The transmission mount uses an aluminum adapter at the rear of the block, and coolant flows through it. It is more likely a seal(ant) failure at the adapter than a head gasket issue. A "firm" coolant hose is normal, under most normal conditions. Nothing you describe indicates a head gasket failure. It is more likely you have a seepage at the tranny adapter, which previously relieved the residual coolant system pressure. If the stop-leak did it's job and stopped that leak, you will probably make it through the season without further issue. It is certainly prudent to keep an eye on things, though.

[rapidoxidationman]

Is your radiator hose still hard in the morning, with a cold engine?

[markelectric]

Truck is still at the mechanics shop. I only saw it as I was passing thru...

[More Power]

I've run a diesel with a loose coolant surge tank cap, thinking less pressure would help with a head gasket problem that results in over-pressurizing the cooling system... Its doesn't. A loose cap (or lower pressure cap) just makes the problem worse - causing more combustion gases to work through the cooling system and force more coolant out through/around the loosened cap.

I agree with others here that you may not have a head gasket problem.

One clear indication of a head gasket problem is soot will begin smudging the inside of the coolant surge tank as combustion gases work their way through the cooling system.