Hey, all...

Still trying to figure out why my truck is overheating. No codes, fluid levels are all OK, coolant is nice and green and flowing through the system. I replaced the plugs and found that they all were toast, one had a shattered electrode! Rotor and cap also didn't look so hot, so I replaced them, too. Engine runs smoother, but still overheating and knocking when I accelerate or try to drive up a steep hill.

I was talking with my buddy the big-rig mechanic, who also seems to know a whole lot about Ford F-series trucks of various years, and he had some suggestions.


RE: Knocking and overheating - He said that it's likely that the inside of the cylinder heads are crusty and that I should probably remove them and have the carbon cleaned out, then have them resurfaced before re-installing. This sounds like something to check, as the knocking got slightly better when I ran a tank of higher grade fuel. Can anyone comment on this?

RE: Preventative measures - He also said that it's about time (144K miles) that I remove the oil pan and replace the oil pump. He said that they give out at about 150K miles. Anyone comment?

Thanks much for any advice.

 

Do you have low oil pressure?If not dont fix it if it isnt broke.Did you try to flush out the radiater?Professionaly?Atruck with that many miles could have a clogged radiater.Good luck.Stuck thermostat?Maybe?

 

I concur with the radiator as a good source of grief.

Even after a flush it can still be bad. The problem is they get clogged. They have tiny tiny passages. Really the only way to know is a couple of ways. The easiest is to completely drain it and then measure the amount of coolant added against the sepcification capacity. The alternative would be to have an Infra Red test done on it. They have equipment that will meaurse the eveness of heat transfer and can "see" if its clogged. The problem with this process is, you can replace a radiator completely for about the cost of this procedure.

I have 2 different Ford radiators go bad from being clogged. I regularly flushed and maintained them.

As to the heads loading up. If they were carboned up I'd expect to see some other problems besides a simple overheat with a ping. Even so, you can clean them without removing them. They have processes now that introduce steam and solvents into the cylinder while the engine is running that will clean the heads to new condition.

Hope this helps

 

a l

 

Thanks, y'all...

I'll probably check the radiator and the fan clutch. The cowling looks fine. I've replaced the water pump and T-stat within the past 30K miles, the top radiator hose is hot when at running temp, so I'm guessing the T-stat is working. The water pump isn't leaking visibly, but I'll check to see if coolant is flowing. And I'll probably hafta brush out all those bugs!!!

I sure hope the radiator is the problem. I've got precious little time and money to deal with the heads right now.

 

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If your radiator is indeed clogged it wouldnt matter if you were travelling on the hyway or sitting at a stoplight, it would get hot just the same.

This is because the water is not passing through the radiator, so the amount of air that you moved past it is irrelevent.
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Ummm not to start a debate here but actually it does matter. Given the same amount of water present for both hiway and stoplight, the coolant would be kept cooler at speed than it would at rest. The quantity being diminished simply wouldn't have the same amount of heat transfer capacity. It may have enough to keep it at a warm range at highway speeds, but a hot range at sitting speeds. It would circulate and cool say 85% of the total volume because that 15% is not available for cooling/re-circuilating. At speed it has a chance to make up for it by sheer air volume. A given amount of water can only hold so much heat. After that it can't absorb anymore.

Your point about the passages being clogged and capacity measurmeents is well taken. It would only make a difference if the passages were clogged and "holding" water rather than simply preventing flow. But clogged passages could also prevent water from completely filling due to the air pockets they would force to happen

The present day cooling systems don't require much coolant to begin with so a quart or so of capacity would be a difference in running temperature.

By the way Tom radiators are relatively cheap now. The last Ford I did was $100.00

 

It may indeed be the radiator.

I checked this morning after driving to work. The fan was working fine, the hoses were all quite hot. The few inches of radiator on the side where the hoses connect was hot, but the rest of the radiator was cold, like ambient-air-temp cold!!!

I'm gonna try a radiator flush, but if that doesn't work, I'll spring for a new radiator.

 

If you decide to flush your radiator instead of replacing it then get it done by an experienced pro. He'll be able to tell you if it's worth fixing/flushing or if you should get a new one.

I like the idea of replacing the thermostat and would also recommend that you check your ignition timing. If it's off it can cause pinging & oveheating as you described.

Good luck.

 

a l

 

SpaceMan:

I think we are in agreement. We just seem to articulate it differently. I can see what you are describing and won't disagree. I can also speak from practical quart low in a 2 gallon system experience.

The main thing is we are agreeing that he needs to change a radiator most likely....

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"The quantity being diminished simply wouldn't have the same amount of heat transfer capacity."
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Should have read "The diminished quantity being cooled simply wouldn't have the same amount of heat transfer capacity".

Like I said I didn't wish to start a debate. Sorry I made us both spend all this time typing.

 

A l