Diagnosis: At highway speeds of 60 to 75 my 88 F-150 would over heat. After returning home discussed this with a few friends with the collective answer being a head gasket.

Since I am going to spend allot of time changing the head gasket, what else should I change/clean/inspect while I'm in there?

Kevin
1988 F-150 5.8

 

do a compression test.

 

quicklook2, I am thinking more along the lines of after I have the head off. Anything?

 

you know for certain that it is a head gasket? did you do a compression test? what if you took it apart and found it was maybe a clogged cat convertor or timing was off because of something broken.

 

I'm also curious how the headgasket conclusion was reached.

 

It could also be a radiator problem...either not enough water flowing through it, or not enough air moving across it. Changing head gaskets is a major undertaking. Are you certain that is what it is?

 

I concur - you should DEFINITELY make sure it's a head gasket before you rip the motor apart when it could be something as simple as a thermostat.

If you're having overheating problems, you should start with these steps:

Run a bottle of cooling system flush through it for a couple hundred miles and then flush it out with the prestone flush kit. Change the thermostat and the water pump. Refill with 30/70 antifreeze/water. That will cure 90% of overheating problems.

Also check the timing. Too far advanced timing can cause overheating.

Are you also seeing your coolant go missing? Is it showing up in the exhaust or the oil? Those are classic headgasket issues. Are you sure it isn't a leak (if you're missing coolant)?

 

andym, my thoughts EXACTLY. That is solid advice that I would follow if I were you before I moved forward.

 

I agree. Also if water travels through the radiator too quickly it will not get a chance to cool, dont forget bout that either...

 

I was very solid with the head gasket repair after discussions with a few friends. Here is the information I gave them.
I had made a trip a few weeks back leaving late at night as well as passing through a number of rainstorms without any problems. On the return trip I left at noon (Fort Worth to New Orleans in July) doing 70 on the highway, and soon started having over heating problems. I was able to cool it off with a water hose being sprayed thru the grill while running numerous times. The first few times I checked the water level, and each time it was fine. About half way through this 600-mile trip I removed the thermostat, it slowed the overheating, but did not stop it. Each time I got back on the highway it was fine for about 15 to 20 minutes, after that the temp would continue to climb until I had to pullover again.
I do remember the following oddities. When checking the water level I noticed a lot of air bubbles in the radiator while running. After cooling with a water hose it would not get hotter while I was looking around trying to figure it out. During a 10 mile stretch at 50 MPH the temperature was just above normal, and went right back up upon return to 70 MPH.
Today I drove it around for 40 minutes, not getting above 30 MPH with A/C on without any problems.

 

again, you need to get a compression check.

unless you want to replace the whole engine, stop driving it and get it diagnosed and fixed before it blows up.

your 'friends' will not be the one without a vehicle.

if you drove it for 40 minutes with the air on, than it is not the head gasket, it would have overheated big time.

i hope we are helping you. good luck.

 

It sounds to me like your radiator is clogged up. A flush should help, but may not cure it entirely.

I would do the compression check first. It's free. If you do have a blown headgasket, it will definitely show up. And it will also tell you what side it's on so you don't have to pull both heads.

 

This is not a daily driver, and I will check the compression very soon. The radiatior is 4 years old so I think it's fine.

 

hmmm... I'm surprised no one has suggested cheecking the clutch fan too.

 

Because the fan doesn't do much of anything at speeds of 60 to 75 mph. It's just along for the ride.