5.0 Running Hot

[billt]

Hi, This is my 1991 LX 5.0. The only problem I have with it is like so many, IT RUNS HOT! Thus far this is what I've done to it with no real improvement. New Radiator, (Jegs Dual Core Motorcraft), 180 degree thermostat, (Stant), Ford Silicone hoses, Direct drive Flex Fan extended to within an inch of the core. It still runs hot in traffic. Here in Arizona in the Summer forget using the A/C. I have to lower the windows, turn on the heat and fan to keep the temp gauge from going through the roof. Even then if I'm stuck in traffic it will go sky high. I've been told an electric fan will help, but I don't feel like going through all that work and expense if it is just going to be like everything else, basically a waste of time and money. I know I'm not the only guy with this problem. Has anyone else solved this issue? Thanks in advance, Bill T.

 

[cervinistang]

in michigan i always run dead middle... sometimes i think its broke. but it increases up there just fine.

have you tried that water welter stuff? sometimes its the little stuff that makes miracles.

 

[Notchbck93]

Get yourself an infared thermometer. That car should easily stay cool, even in 130 degree heat.

Make sure she doesn't have any air pockets in the cooling system, unscrew your temp sensor and bleed any air out if need be.

Check timing!

Also, ensure the water pump is going in the right direction or is a reverse flow one, someone may have installed the wrong pump on that old girl.

Hopefully you don't have a cracked head, you would usually know by it delving out white smoke, or over pressuring the cooling system causing the over fill to barf.

Worst case, I have solved two overheated Fords with two bottles of water wetter. My buddy with his blown 5L ranger had some over heating problem, I had him throw two bottles of water wetter in and all be darn, she ran cool from that day on.

And for goodness sakes, get yourself a real cold air kit! I can't imagine the under the hood temps in AZ, your sucking it all in Son.

 

[billt]

No air pockets, OEM pump, timing is right on. Tried the Watter Wetter, (2 cans), didn't do much if anything. Coolant is flushed every year. Bill T.

 

[Darkwriter77]

Do you have a fan shroud still on there? If not, then your fan won't pull jack for air through that radiator at idle or low speeds (below 45 MPH). If it's getting hot when you're cruising ABOVE 45 MPH, then check if you're missing the air dam that goes underneath the radiator support on the '87+ models - y'know, the big rubber or plastic "ground effect" kinda thing that traps air from scooting under the car and redirects it up to/through the radiator.

Also, have you ran a compression test on the motor, yet? If you find two or three cylinders on one bank with numbers lower than the others (like 80 psi or less while the rest are 100+ psi), then you've got a blown head gasket.

I've been fighting cooling issues on my '84 for awhile now and I've narrowed it down to the radiator itself being full of deposits (it's the original from '84 and some doofus prior owner ran straight water in it for ages ), the need for a fan shroud, and a proper fan and clutch (flex fans SUCK). You could switch to an electric fan to help with the low-speed/idle cooling problem, and free up a few horses while you're at it, you MUST upgrade your alternator to a 130+ amp alternator (3G alts rule) because ANY electric fan pulling enough air to cool a 5.0 will draw more amps than the stock alternator can really afford to put out, especially if you have the headlights and/or any other accessories running.

Most common causes of overheating:

1. Failed or missing thermostat;
2. Plugged-up radiator;
3. Blown headgasket;
4. Lack of airflow to or through radiator (missing air dam and/or fan shroud, or road debris buildup);
5. Bad fan clutch (allows fan to "slip" too much);
6. Incorrect or failed radiator cap (lower cooling system pressure = lower boiling point);
7. Significant coolant leak (water pump seepage, leaky/ruptured/rotted hoses, loose clamps, etc.);
8. Timing WAY too far off (usually results in other obvious drivability issues);
9. Air pockets in coolant system;
10. Your name is Dave and, thus, anything that can go wrong with your car WILL go wrong, especially around paydays or when you have excess funds

 

[billt]

You can see the fan shroud in the photos. The faster I go, the cooler it runs. It runs the hottest in traffic, and at low speeds. Get enough air moving through and it's fine. Every Fox Bodied 5.0 out here has the same problems. I'm told electric fans are the best way to go, however until I know for sure it will help, there is no point in it. Everything I've done to it hasn't hurt, but no great improvement either. Bill T.

 

[87coupe50]

Maybe this will help

Long story short (ened), but I recently had the same issues (and a whole slew of others) after bringing my car out to Kansas. Durign the trip out I noticed that the car was running warmer than normal (no a/c). After I got here I installed an a/c conversion kit cause I was tired of sweating inside the car. Stop and go traffic or just plain stops would cause the guage to continue rising. Stayed cool on the highway but If it was already hot by the time I got to the freeway it would take forever to cool down. Replaced the clutch fan. New t-stadt and 2 core alluminum rad. Flushed the system twice, ran straight water for a little while (was a little better). Then tried water wetter. Because of all the other little issues I was having I recently changed the lower intake gasket. The ends of the gaskets by the water jackets were all tore up. All kinds of splits and cracks. Looked like the coolant was slowly leaking into the adjacent cylinders. Resealed everything and it's good as new. I had put in a 180* unbalanced t-stadt and I haven't seen it get above 188 (a/c on) since replacing the gasket. Granted, the temps here have been a lot cooler than 130*

 

[FrankenStang]

You can see the fan shroud in the photos. The faster I go, the cooler it runs. It runs the hottest in traffic, and at low speeds. Get enough air moving through and it's fine. Every Fox Bodied 5.0 out here has the same problems. I'm told electric fans are the best way to go, however until I know for sure it will help, there is no point in it. Everything I've done to it hasn't hurt, but no great improvement either. Bill T.

Chances are Darkwriter77 can't see the pictures. He's at work and they're probably blocked.

 

[billt]

Chances are Darkwriter77 can't see the pictures. He's at work and they're probably blocked.

Sorry, didn't think work blocks photos these days. Bill T.

 

[FrankenStang]

Sorry, didn't think work blocks photos these days. Bill T.

Sometimes photos are blocked for me too. Usually Photobucket or Imageshack are blocked. Depends on the comp's settings.

Nice car and welcome to Stangnet, btw

 

[Darkwriter77]

Yeah, the photos were blocked. I can see 'em now here at home. But still, it's a fair question anyhow - you said you put on a flex fan, and considering the previous owner of my '84 put one on mine but decided to get rid of the shroud at the same time, I figure it was a POSSIBILITY he could've removed the shroud since the pics were taken, but ... bah, moot point anyhow.

If you're having problems cooling at low-speed, but it cools down when you get up and moving at a cruise (above 45 MPH), then the problem is insufficient airflow through the radiator at low speeds or idle. Flex fans are crap for a variety of reasons: 1. They're noisy, 2. The have a nasty tendency to come apart at really inopportune times and destroy things, 3. The sharp aluminum blades and the lack of a fan clutch make for a VERY effective finger-cutter-offer, 4. The blades flatten out as the RPM's go up (pretty much at any rate above idle), so essentially the harder you run the motor, the less air it pulls (thus the heat-up in stop-and-go traffic).

You could convert to an electric fan, true, and as mentioned you will need to upgrade your alternator at the same time. Swapping to electric has its advantages, but it's also pricey. Also, there's more things that can go wrong with that; connection problems, fan motor burning out, defective fan relay, defective fan switch, blown fuses, drain on charging system (depending on how it's wired up and if you upgrade the alt), etc. etc. etc. Personally, I'm becoming more and more partial to stock-style fans over electric just for the sake of simplicity and general reliability. It just depends on what your budget is and whether you want to stay stock or if you've got a lot more mods in mind later on and wanna squeeze out every last bit of HP that you can.

If you wanted to go the simpler route and also keep things looking stock (it'd look darned nice in that clean of an engine bay), just pick up a new OEM-style fan blade and fan clutch from Autozone. It's around $40 for the fan clutch and about the same for a fan assembly, takes just a few minutes to bolt the thing on there, and your car will no longer sound like a Hoover vacuum cleaner like it surely does with that useless flex fan. You might also need to buy four slightly shorter bolts (get Grade 8) because when you eliminate the flex fan spacer, you're going to have an extra 3" or so of bolt that you can't use to hook up the OEM-style fan. Can't remember exactly the thread pitch, but if you just take a bolt off the flex fan and run down to the store, you can thread-size it with that and just subtract the length of your flex fan spacer.

Btw, that's a VERY nice n' clean engine bay ... except, uhhh ... what's up with the Cobra plaque on a stock 5.0 intake?

 

[billt]

I agree with your assessment of the electric fan which is why I haven't gone with one. When I bought the car, (it was 6 months old), it was totally stock, except for that Cobra plate on the intake. I had the overheating issues from day one. It was worse when I lived in Lake Havasu City. I changed out the OEM Vicious fan assembly, dropped down to a 180 degree thermostat from 195 degrees. Went with the larger radiator and the Flex Fan and spacer all at the same time. In the Winter it is fine. I have zero temperature issues. It starts to get bad on days when it gets over 100 degrees. A couple years back I went to Yuma in August and it was around 112 that day. It ran fine on the highway even with the A/C on, but as soon as I got into the city, the gauge went higher and higher until I had to shut off the air, open the windows, and turn on the heater and fan to keep it down. I agree it's an issue of it not getting sufficient air at lower speeds. I'm beginning to think it's a design issue because of all the people I've run across over the years with these cars who have the same problem. The only other thing I could do is run a larger pulley on the crankshaft. But if I do that I run the risk of over revving everything else at high engine RPM. I've lived with this for the last 17 years and it looks like I'll have to continue to do so. I'm running out of ideas and patience. Bill T.

 

[jd-hart]

Do you have an aftermarket gauge to see what the temp is really at? Using the stock gauge to determine your problems could be a problem in of itself.

Nice looking engine, but I would also get rid of the air filter like that. You have to be bringing in some serious hot air from that.

 

[jd-hart]

On a side note, where did you get your A/C compressor? Is it new, or did you really clean it. Looks good

 

[Ramsey 93]

I went to an electric fan, wasnt big enough, so i got the mark 8 fan.. still didnt cool as well as the stock clutch fan. So i am back to a stock clutch fan and very happy with it.

 

[billt]

The temperature gauge and the A/C compressor are both factory stock. For cleaning all I have ever used is Simple Green straight from the bottle on a COLD engine. I soak everything, and I mean everything. I cover the Air filter with a plastic bag, or else remove it. I then rinse with a garden hose, blow everything as dry as I can with compressed air. After that I start it, and run it until it is completely warmed up, then hit all of the plastic with Armorall, or a similar product. I went with the K&N Filter Kit as shown mainly because shortly after I bought the car, I went to replace the air filter element and found a large crack in the plastic, factory stock air box behind the filter. It was allowing air to enter behind the filter. I forget what Ford wanted for a factory replacement, but it was ridiculous. So I bought the K&N Kit. The engine seems to breath a lot better with it. Bill T.

 

[billt]

I went to an electric fan, wasnt big enough, so i got the mark 8 fan.. still didnt cool as well as the stock clutch fan. So i am back to a stock clutch fan and very happy with it.

Thanks for the information on the electric fan. Sometimes what people recommend isn't always what works. Nothing like first hand knowledge. Bill T.

 

[monte87]

The answer to your question here is ELECTRIC FAN. i know-You dont wanna hear it. but exactly what you stated is the dead giveaway. Your car runs cool when moving and while in traffifc it runs hot. That means there isnt enough air flow across the rad when not moving, hence the electric fan will eliminate that prob. if your gonna go E-fan, do yourself a favor and get a MKV8 fan and be done with it. But if you choose to skimp out and go black tragic or proform or any of the others-You will have already wasted $$$ on those fans when in the end-You will gain nothing but more aggravation and spend more $$$$$$$ in the end trying to solve yoru initial prob.-Getting the MK8 in the end anyways. I have been there and done that-So i want to spare you the unecessary headaches.

Good luck to you my friend, Ant
~SEMPER FI~

You can see the fan shroud in the photos. The faster I go, the cooler it runs. It runs the hottest in traffic, and at low speeds. Get enough air moving through and it's fine. Every Fox Bodied 5.0 out here has the same problems. I'm told electric fans are the best way to go, however until I know for sure it will help, there is no point in it. Everything I've done to it hasn't hurt, but no great improvement either. Bill T.

 

[monte87]

If your completely stock and not intending to do H/C/I or S/C which will only increase the heat factor in the futire-You can always just stick with the a POLICE FAN clutch and fan, for simplicity and relaibilty-Which worlks quite well-with a stock set up. On my car with H/C/I and high stall, 4.10's she is always revving increasing temps-So that wouldnt and didnt work for me. But when stock-Its a different story.

 

[jd-hart]

I would get an autometer temp gauge and see how hot the car really is.