I have an 02 Screw that is pushing coolant from overflow tank badly and the temp gauge will go all the way to hot then fall back to normal within seconds. It's at the shop now but I'm fairly sure it's a headgasket.
The truck has 177,000mi on it. Should I fix the hg or go for a reman longblock?

 

By "pushing coolant from the overflow tank," do you mean it's using up coolant (where you have to keep adding) but you don't see any obvious leaks? Or that it's making coolant flow out of the tank?

If it's the former -- using up coolant without any obvious leaks -- then indeed, the most-likely cause is a blown head gasket. They can also confirm this with a compression check, but not rule it out...I've found that even with a blown head gasket, a compression test can still be inconclusive and read semi-OK.


The head(s) can be removed without them having to pull the motor.

When they pull the heads off to check/repair the head gaskets, have them take a look at the condition of the valves and valve guides. If indicated, this would be the time to have them perform a valve job (as long as the heads are off anyway).

If the heads/valves are OK, then they can just put them back on with new head gaskets and you should be good to go. No need to have them pull the motor or replace the whole motor unless there's evidence of bottom-end problems with the main bearings or connecting rod bearings.

Most cases, unless a motor has been abused or not maintained (lack of oil changes and such), the lower end of the motor (main bearings, connecting rod bearings, rings, cylinders) is still fine at this mileage. They can look at the condition of the cylinders with the heads off, of course (to check for scoring and such).

Just my $.02 based on a recent rebuild of a '99 Taurus motor with 190,000 miles on it. It was using coolant but had no detectable leaks, and was running poorly. On the suspicion that it had a blown head gasket (it did), I decided to pull the motor and rebuild it just for the experience. I had a valve job done on the heads, but when checking the crankshaft/camshaft/piston/cylinder measurements with a micrometer, everything was in perfect shape. So unless you really want a new/reman motor, having them pull the heads and fix the blown head gasket (if that's indeed what it turns out to be) would be what I'd suggest.

 

It is pushing coolant out the tank.

 

Did you replace the thermostat yet? Sounds like it may be sticking and getting way to hot before finally opening and then allowing the collant to circulate in the motor.

 

The tstat was replaced 2 wks ago when the coolant cross over sprung a leak. It could actually be the tstat as this problem only started after that repair as new doesn't mean anything.

 

Sounds like a bad t-stat to me.

 

Could be either a T-stat or HG. Simplest way is to hydrocarbon test the coolant, if exhaust gases are present... it's a HG.

 

You'll have better luck with the 92 or 94. I'm pretty sure the 94 works best. Allot of problems with the 87's. If the stats the problem.

And yes pushing coolant from the overflow isn't a gasket leak. Gasket leaks give off a false boil effect inside the degas bottle,- or expansion tank.

 

Hm, actually pushing coolant out the tank (after replacing the TStat to eliminate that as a cause), makes me think next of a clogged radiator or similar blockage in the system. Does the amount of coolant coming out the tank increase if you rev the engine? If so, that's a further indicator of a blockage -- the water pump pushing coolant against the blockage finds an easier exit to come out of the reserve tank instead.

That said, if the problem started all of a sudden as opposed to slowly building over time, would lean against a clogged radiator (though there could be a blockage elsewhere that started after the repair work was done -- sorta like a clot breaking loose after surgery and causing a stroke).

 

Sorry it took so long to get back. The pushing coolant problem was from me apparently overfilling the tank. They had it in the shop and couldn't get it to over heat but I went to the store convienence store and left it running and came back out and the temp gauge was pointing straight up. I put it in gear and it imediately started cooling off and 100 yrds later it's back normal. The coolant is a dirty red brown.

 

I would change out the old coolant as soon as i could.
If it starts getting too warm on idle, clutch fan might
be going bad.

 

Before you change the coolant, hydrocarbon test it.