Excessive Pressure

[expeditionstig]

So I had a radiator hose leak and no front heat up until this week. I threw another hose clamp on the top radiator hose at the radiator which has stopped that leak, but now the hose is hard as a rock and is leaking where it connects to the thermostat housing. Way too much pressure. And to top if off my coolant smells like fumes or gas.

I'm thinking HG now. :/

I just find it strange that my Oil is CLEAN. My coolant is nice and bright green, just smells. Truck runs GREAT. No shudder, no overheating, great power, etc. I've been taking it on 4-5 hour trips over the mountains and it purrs right along.

Any other ideas? or face the music with the HG? I don't have the funds to take it the shop, and no where to work on it.. So I may end up driving it this week and parking it.

 

[redrebel66]

From the "hard hose" condition your talking about it sounds like the thermostat isn't opening.

 

[expeditionstig]

That would be neat if that's all it was. I don't think the tstat has been changed in 6+ years. But if it was stuck closed, wouldn't it overheat?

If I get some extra time tomorrow, I'll go to napa and pick up another tstat and see if that helps.

 

[stamp11127]

Give the hg some thought. What path would the gas have to take to get into the coolant? If a cylinder leaked it would pressurize the cooling system past the rating of the cap and puke the coolant. I would flush rhe system and replace with new coolant. If it ended up with the gas smell I would dig deeper.

 

[toms89]

Leaky head gasket does not necessarily mean you will get coolant into the oil. I have blown enough head gaskets in the past via aggressive tuning and boost to know this well. Only in more advanced cases does it leak bad enough to introduce coolant into the oil. In extreme cases you can hydraulic a piston.

During the power cycle, inside the combustion chamber, pressure is quite high. This wants to lift the head and is when the head gasket is most likely to leak gasses into the cooling system. Its the compression ring around the cylinder (portion of the head gasket) that is failing here first to contain the combustion gasses. Eventually as the breach progresses it can leak both ways.

With the older cooling systems where the radiator cap was ahead of the overflow bottle puking coolant was a common symptom of a leaky HG. It is a bit less so with the radiator cap on the coolant bottle due to the expansion air space inside it. It will typically vent the air first as it exceeds the caps rating until the gasses introduced get bad enough to overwhelm the system.

 

[toms89]

You might try replacing your radiator cap, flush the system as mentioned and make sure you have adequate expansion space as marked on your coolant bottle. Make sure you use the correct coolant ratio as well.

I might suspect the thermostat or waterpump as a potential source of excessive pressure, due to lack of flow, but the fact you say the temps are normal makes this unlikely.

 

[expeditionstig]

I threw a napa radiator cap on with no difference. I could try the thermostat when I get some time in the next few days.

I flushed the system about a month ago when I thought my heater core was clogged. Has fresh coolant in it (other than smelling). It's losing coolant, but I think it's from leaking at the tstat connection. No white smoke on start up, or when I hammer on the gas.

 

[tonydiv]

A leak down test will help you determine id you have a leaky head gasket.

I would put a pressure tester on the radiator and see what the pressure really is when the truck is running.

 

[expeditionstig]

I will try to run out and get a leak down tester from napa tomorrow. and if it's negative I will replace the thermostat and see what that does.

 

[splintrcel]

The coolant lines do where out. Coolant will make the rubber stiff after while thus not making a good seal. I would replace the leaking line. Odds are it just wore out but also you can check the coolant pressure. Any auto store sells a kit that tells you the coolant pressure.

 

[toms89]

I will try to run out and get a leak down tester from napa tomorrow. and if it's negative I will replace the thermostat and see what that does.

You need an air compressor to use a leakdown tester. It may or may not show up during the test as combustion pressures are significantly higher than the 100 psi or so you run during the test. Depends on how bad she is leaking.

If it does leak it will show up as bubbles in the coolant as your are doing your test on whatever particular cylinder(s).

The following type of tester is fairly reliable for presence of combustion gasses in the coolant.

Amazon.com: UVIEW 560000 Combustion Leak Tester: Automotive