Truck Getting Hot

[Skandocious]

Yeah only hot at idle indicates to me that the fan is probably not doing it's job. Cools off when you're driving because the wind coming through the grill is doing the cooling for you.

 

[flareside_thunder]

Pulled the flex fan off...the factory clutch fan moves more air....I think it may be the pump but I can see water circulating extremely well in the radiator. Got hot goin up the interstate today at 70 MPH.......really really startin to tick me off.

 

[Old_Paint]

This is beginning to point at bigger problems. However, did you put a thermostat in? As another poster said, not having the t-stat in will let the coolant go through the radiator too fast to cool down. The thermostat serves two purposes. 1. All but stop coolant flow until the engine gets up to the rated temperature. 2. It acts as a flow restrictor to let the radiator do it's job.

However, just because you can see flow looking down in the filler neck, that does not mean the majority of the radiator isn't plugged up. The bottom half of it could be plugged, and you'd stilll see a ton of flow with the cap off. The problem is, only half the radiator would be removing any heat. If anyone has EVER used stop-leak in that system chances are it's clogged in a lot of the lower tubes. One one of my '86 T-Birds, I had a very similar problem. Could see flow, but, it was all going across the top third of the radiator. Bottom 2/3's was doing nothing to cool. There are two ways to diagnose this. One, an infrared thermometer, and look at various places on the radiator. Should be hottest on the left end, standing in front of it, but a fairly even temperature drop as you check left to right. Plan B is to take the radiator to a shop that can open it up and rod the tubes. If you choose Plan B, it will probably be cheaper just to get a reman radiator.

If you're certain there is no blockage in the radiator, and have the t-stat in it, and a functional fan of some sort, it should NOT get hot at 70 mph. The fan isn't even necessary at that speed. That's why it has a clutch. Dunno if you've ever been in a vehicle that the fan clutch siezed on, but it'll make a '86 T-Bird sound like a Boeing 747 coming down the highway. And your fuel mileage will SUCK. And, believe it or not, it WILL RUN HOT. With the fan siezed, it causes too much turbulence through the radiator and the air does not remove the heat as well. I've been called out on this theory, but I've also driven the car with a siezed fan on the interstate. If the coolant goes through the inside too fast, or if the air goes 'round the outside too fast, the cooling efficiency of a radiator drops dramatically.

If it's forcing the coolant out of the system, but is't getting up to the red mark on the gauge, something is pushing that coolant out. This is normally a failure of a head gasket between the compression chamber and the water jacket. If it's pegging the gauge, there is something seriously wrong with the flow in the cooling system, or a very seriously blown HG. There's just not a lot of adjustment or leeway in the cooling system. Normally, it works, or it don't works. Don't works after it's worked before usually indicates a component failure of some sort.

Are you sure you have the right WP for your truck? Some of them were designed for reverse rotation on different SBF's. They'll work, but not so good. I can't remember which is which, but if the pump is designed to be driven by the inside of the belt, that's backward to what you need. The pumps for any SBF that uses the the outside of the serp belt is designed to rotate counter-clockwise facing the front of the engine. The same pump housing is used for other legacy SBF's that used V-Belts and was driven by the inside of the belt. They turned clockwise. It DOES make a difference.

I'm not trying to say anyone is an idiot or be a know it all. I'm just trying to point out some things that will have to be checked. But, if you haven't put the t-stat back in, especially at highway speeds, it WILL overheat. Been there, done that with a 1968 Opel that I thought would do better without the T-Stat. Man was I wrong.

Check your coolant really close for any contamination that looks like soot or ash. It may not be much, but that's a sure sign of a blown HG. Let it sit over night, and while still cold, check both the reservoir and the radiator to see if you see any black dusty looking particles floating on the surface, or something that looks like an oil slick. It doesn't take much of a HG leak to be a BIG problem for the coolant, and this will only aggravate itself.

 

[flareside_thunder]

Yes, there is a 180 Stat in there now.....it helped tremendously with it overheating at idle. I've had the truck since it had 81k old man miles on it and I have never used stop leak, it's nothing but a bandaid to a bigger issue IMO. I'll take an IT to it and see temp changes throughout the radiator, I still think it's the issue but not looking forward to digging out money I don't have for a remanned one. (Maybe I'll find who stole my 4 core and repo it) I'll check the fan clutch today when I mess with the timing. I am pretty sure it's the correct waterpump as it's been in the truck for 2 years. I am however starting to think the pump is cavitating at higher speeds. This is the waterpump I have: http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Water-Pump-ASC_3130088-P_54_R|GRPCOOLAMS_581439628___

I'll also check for ash, soot or oil today in the cooling system;although none has showed up thus far.

 

[1985 Ford F-150]

Id get another water pump I got one from them and it died on me in a month. Go get a good high flow one from Jegs or summit.

 

[blackhat620]

Coolant overflow in the reservoir yes...Cleaned and thoroughly flushed the radiator out...Wrapped the lower hose with a thick heavy copper wire to prevent collapse.T stat is non existent.......See how she runs tomorrow...if nothin helped then I've already got the head gasket kti sittin in the truck......Also got a line on a 351 too so we'll see numbers for that thing tomorrow! Thanks for the info.

FYI wrapping wire around the outside of the radiator hose will do nothing to prevent collapse. The wire must be inside the hose to prevent collapse.

Yes, there is a 180 Stat in there now.....it helped tremendously with it overheating at idle. I've had the truck since it had 81k old man miles on it and I have never used stop leak, it's nothing but a bandaid to a bigger issue IMO. I'll take an IT to it and see temp changes throughout the radiator, I still think it's the issue but not looking forward to digging out money I don't have for a remanned one. (Maybe I'll find who stole my 4 core and repo it) I'll check the fan clutch today when I mess with the timing. I am pretty sure it's the correct waterpump as it's been in the truck for 2 years. I am however starting to think the pump is cavitating at higher speeds. This is the waterpump I have: http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Water-Pump-ASC_3130088-P_54_R|GRPCOOLAMS_581439628___
I'll also check for ash, soot or oil today in the cooling system;although none has showed up thus far.

Generally a water pump will only cavitate if 1) the system is low on water, 2) there is to much restriction in the water jackets causing the fluid to backup at the pump, 3) fluid boiling (note if there is a leak or air bubble in the system, the boiling point will be substantially reduced), 4) damaged impeller

So far you have performed the following repairs:
Flushed cooling system
Installed new T-stat
Confirmed fan operation
2-year old water pump

Since you are overheating at speed (above 30-35 mph), then one or more of the following problems are occurring:
1) Low coolant level (air bubble trapped in system)
2) Collapsed lower radiator hose
3) Plugged water jackets or radiator
4) Incorrect engine timing (if there is to much timing advance at speed you will get overheating and power loss. This is caused by the timing advance system or curve not working properly.)
5) Bad water pump

I would check the following:
1) Radiator for hotspots with an electronic thermometer (make sure the enging is warm and t-stat open).
2) Pressure test the cooling system
3) Engine timing both base and advanced

If all of the above check out okay, then you may want to replace the lower radiator hose, and if this does not help then pull the water pump and make sure the impeller is not damaged. Unless the cooling system has been severly neglected i doubt the water jackets are plugged.

 

[blackhat620]

Go get a good high flow one from Jegs or summit.

A high flow water pump will only lighten your wallet, unless you have a highly modified engine they are un-needed. Also to much water flow is as bad as to little. If the water pump is moving to much coolant the coolant can back up at the pump causing cavitation & overheating, and if the coolant is moving to fast the radiator cannot properly perform the required heat exchange.

Also just because you had a water pump fail within 30 days does not mean that you did not recieve a defective pump, all manufactures have defects. If there was an air bubble or leak in the cooling system it will cause the pump to cavitate and destroy the pump in short order.
In your earlier post you said your truck was overheating and low on coolant yet you saw no visible leaks. An internal leak will cause the system to lose coolant, overheat, and water pump cavitation (resulting in premature pump wear).

 

[1985 Ford F-150]

Yeah thats the 85 thats doin it I think I know what the problem is with it. Its got that wierd recovery bottle on it and the hose might be a little loose so im gonna put a hose clamp on it and see if it helps. Another thin that could be goin on with it is its just sittin in that recovery bottle then it evaporates instead of goin back in the radiator. It dont have a cap on that recovery bottle but I did stuff a rag in the hole as tight as I could get it. It also dont happen very often this is the second time its actually boiled over the last time was 2 years ago when we first moved out here. Its probly my own fault for not checkin it very often. I dont think its that big of a problem cause the only time it ever tries to heat up is when its either goin over that pass or towin somethin heavy. Also the water pump that was bad was on my 390 and it siezed up tight so Im pretty sure it was just a bad pump from the start.

 

[blackhat620]

Yeah thats the 85 thats doin it I think I know what the problem is with it. Its got that wierd recovery bottle on it and the hose might be a little loose so im gonna put a hose clamp on it and see if it helps. Another thin that could be goin on with it is its just sittin in that recovery bottle then it evaporates instead of goin back in the radiator. It dont have a cap on that recovery bottle but I did stuff a rag in the hole as tight as I could get it. It also dont happen very often this is the second time its actually boiled over the last time was 2 years ago when we first moved out here. Its probly my own fault for not checkin it very often. I dont think its that big of a problem cause the only time it ever tries to heat up is when its either goin over that pass or towin somethin heavy. Also the water pump that was bad was on my 390 and it siezed up tight so Im pretty sure it was just a bad pump from the start.

Yes a loose hose to the recovery bottle can cause coolant to be lost when the engine is hot, and not allow the coolant to be drawn back into the engine when it cools. Evaporation is going to be minimal unless you live in the Sahara desert and only run pure water, not to mention you will only be losing the small amount from the overflow bottle. Tighten the hose and get the proper cap for the overflow bottle, a rag is not going to do anything useful.
As far as only overheating when worked hard, that could be from a partially plug radiator and/or water jackets, incorrect engine timing, driving the vehicle to hard for the load & conditions.

With all of the symptoms you have posted for your 85 overheating, it sounds like there is a possible leak in the cooling system. Without throwing parts at it, pressure test the cooling system or have it done. Pressure testing is the only easy way to find internal leaks.

 

[1985 Ford F-150]

I know the radiators probly due for a flush cause it was pretty nasty when we rebuilt that motor. Dad didnt think nothin of it so we just threw it back together. Do ya know where I can find the right cap for that? Its just plastic and its been gone for as long as I can remember. Heres another question for ya. Could that radiator have so much gunk and crap built up in it that its not gettin filled all the way? My grandma had the truck for about 8 or 9 years before that my dad bought it off some old guy and dad had it for maybe three years before borrowin it to grandma. I know for a fact that she beat the hell out of it and it got abused and pushed to the limit cause when we got it back it was missin the passenger side mirror, antenna and the red strip from the lariat trim on the tailgate.

 

[blackhat620]

Local auto parts (ie CSK etc) should have the overflow cap in stock.
If the radiator is partially plugged, then the cooling system will have a lower total capacity, but the capacity will not change as the engine warms up. If the radiator is patially plugged then you will have a lower cooling efficiency/capacity resulting in overheating easier. You can try flushing the radiator and see if it helps, however the radiator may be plugged enough to require rodding or replacement. If you know someone with a digital spot thermometer, check the raditor to see if there are hotspots, this will tell you if the radiator is patially plugged.

 

[NeXtras]

question.. do you have the right radiator cap? i know that makes a difference

 

[1985 Ford F-150]

Alright I just never thought about gettin a new over flow cap was that big of a deal. Ill go get one from Napa once we get some money. Ill also try flushin that radiator before winter comes so I dont have to crawl around in the snow. Not sure what pound the cap is on that one but I think its just stock.

 

[flareside_thunder]

I've got a 13 lb cap...so OEM

 

[1985 Ford F-150]

Sorry for the hi jack Junior.

 

[flareside_thunder]

NP man.....

 

[blackhat620]

Alright I just never thought about gettin a new over flow cap was that big of a deal. Ill go get one from Napa once we get some money. Ill also try flushin that radiator before winter comes so I dont have to crawl around in the snow. Not sure what pound the cap is on that one but I think its just stock.

Not a huge deal unless you are getting a large coolant loss because of the missing cap.

I would suspect that you either have a partially plugged radiator, internal leak in the cooling system or both. See if you can find somebody with a thermometer you can use to check for hot spots and a pressure tester.

 

[1985 Ford F-150]

Alright well ill fix that hose ont the bottom of the bottle. Then get a cap and run it for a little while and check the level. Then before winter ill flush out the radiator and put in a new thermostat. I dont know anybody that would have somethin like that. Also forgot to mention that its an ac truck and we dont use the ac so I took the compressor off cause theres some sort of an electrical bug in the system. Would pullin out the condenser help any?

 

[flareside_thunder]

Maybe..you'd get straight on air flow fer sure.

 

[1985 Ford F-150]

Thats what we were thinkin.