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Hi all - I have a 97 F-150, 4.6 liter with 89k miles in good condition. But I have a head gasket leak. No antifreeze in the crankcase, but combustion air is seeping into the cooling system causing a bubble to build behind the thermostat. A test was run on the coolant that confirmed this. The resulting symptom is that the engine tends to overheat at times as the thermostat will not open when it should.
In talking to 3 different mechanics, one has suggested a possible cheap fix. I dunno though. His theory is that a hole can be drilled in the thermostat large enough to accommodate the bubble and the pressure cap on the coolant reservoir could be loosened to allow the air to escape.
It certainly sounds inexpensive, but I have my doubts about how long this would hold up, if at all. Right now the truck is worthless to anyone so I guess I'm in for major damage here. (crosses fingers that the heads are still ok)
Do you know what i THOUGHT you said there.......................................
Quote:
Originally Posted by square peg
Hi all - I have a 97 F-150, 4.6 liter with 89k miles in good condition. But I have a head gasket leak. No antifreeze in the crankcase, but combustion air is seeping into the cooling system causing a bubble to build behind the thermostat. A test was run on the coolant that confirmed this. The resulting symptom is that the engine tends to overheat at times as the thermostat will not open when it should.
In talking to 3 different mechanics, one has suggested a possible cheap fix. I dunno though. His theory is that a hole can be drilled in the thermostat large enough to accommodate the bubble and the pressure cap on the coolant reservoir could be loosened to allow the air to escape.
It certainly sounds inexpensive, but I have my doubts about how long this would hold up, if at all. Right now the truck is worthless to anyone so I guess I'm in for major damage here. (crosses fingers that the heads are still ok)
coolant systems are pressurized for a reason. it raises the boiling point of the coolant. by doing this, you will de-pressurize the system and run the risk of boiling off your coolant.
also, what kind of test was performed on the coolant? i'm having a hard time imagining how you can conlude whatever air is in your cooling system is 'combustion air'.
coolant systems are pressurized for a reason. it raises the boiling point of the coolant. by doing this, you will de-pressurize the system and run the risk of boiling off your coolant.
also, what kind of test was performed on the coolant? i'm having a hard time imagining how you can conlude whatever air is in your cooling system is 'combustion air'.
Bottom line is you must replace the blown gasket or stop the leak. They make several products that have mixed results in sealing blown head gaskets. It would be worth the time to try one of these first. If you do you have to follow the instructions to the letter. Then go to plan "B" and replace the head gaskets. The truck is well worth it.Good luck
I gotta agree with Chief here - the one thing I might try would be K & W Block Seal, as he notes you have to follow the instructions carefully, you end up draining out all the antifreeze and putting this stuff in with just plain water, so watch doing this if you are not in a heated shop, that you don't let the plain water freeze. Then you drain it out and let the system dry, refill with new coolant, and hope for the best.
I would consider this to be a bodge to get you to spring, when you will have better weather and maybe not need the truck on the road daily so bad, and will have had enough time to save up the $ to replace the head gaskets, or have a shop do it.
While the heads are off you can put new valve stem seals on anyway, do some other tidying up type tasks.
If the truck is a rusted out heap, that's one thing, but to me this is still a pretty new truck, and it's way easier and cheaper to do the head gasket replacement than to keep screwing around till you get enough glycol in the oil to wipe out your bearings, or you manage to hydralick the engine with a big leak into one or more cylinders, and you prove to yourself that water really is incompressible...
Hi all - I have a 97 F-150, 4.6 liter with 89k miles in good condition. But I have a head gasket leak. No antifreeze in the crankcase, but combustion air is seeping into the cooling system causing a bubble to build behind the thermostat. A test was run on the coolant that confirmed this. The resulting symptom is that the engine tends to overheat at times as the thermostat will not open when it should.
In talking to 3 different mechanics, one has suggested a possible cheap fix. I dunno though. His theory is that a hole can be drilled in the thermostat large enough to accommodate the bubble and the pressure cap on the coolant reservoir could be loosened to allow the air to escape.
It certainly sounds inexpensive, but I have my doubts about how long this would hold up, if at all. Right now the truck is worthless to anyone so I guess I'm in for major damage here. (crosses fingers that the heads are still ok)
Any thoughts would certainly be appreciated.
First of all, what do you want to do with this truck? Is it a "get you to work and back until it dies" truck? Or do you want to keep and drive it?
If it's the former, I'd suggest the following:
- Remove the thermostat if it's not opening/functioning properly. This will cause your engine to run cooler, and less efficiently, but it can be done. Make sure you replace the gasket on the thermostat housing.
- As NativeChief and Mitch have mentioned, there are products that supposedly seal cracks & leaks in engines. Note that I say "supposedly." Most of them are relatively inexpensive, so what the heck. It's worth a try.
If this is a truck you want to keep, and drive, then find a good mechanic that you trust, and have him fix it. There's no real way around that, unless you can do the work yourself. Gimme3steps can probably give you a ballpark estimate on replacing the head gaskets, but that doesn't take into account that you might have a cracked head. Since I have nothing at stake in the matter, I'm going to guess that it'll be somewhere around $1,500 to get this problem taken care of.
If this is a truck you want to keep, and drive, then find a good mechanic that you trust, and have him fix it. There's no real way around that, unless you can do the work yourself. Gimme3steps can probably give you a ballpark estimate on replacing the head gaskets, but that doesn't take into account that you might have a cracked head. Since I have nothing at stake in the matter, I'm going to guess that it'll be somewhere around $1,500 to get this problem taken care of.
Good luck!
I'd sat that's a pretty close estimate unless an unforeseen problem pops up.
I'd sat that's a pretty close estimate unless an unforeseen problem pops up.
So... If you're looking at a bad head gasket on a V8, do you just plan to do both heads while you're in there?
It'd seem to me that, if I'm going to be elbow deep in the project, I might as well do both sides and get it over with.
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