overheating

[77pony]

Ever since I swapped in my first 351W, about 1987, I've had a hard time keeping it cool. It does just fine during normal driving, but if I climb steady and slow for long periods of time, steady uphill driving for, say, half an hour or more, in high range first gear (auto tranny), on mountain roads that are steep and rough enough to keep me going very slow, but not bad enough to require low range, it eventually gets hot and I have to shut down for a while. Put a trailer of any kind behind it and forget it. I have 33" tires and 3.50 gears, and I wonder if lugging the engine down like that is my problem. I'm going to regear this spring, to 4.11's I think, and I wonder if getting the revs up a little bit while climbing slow like that will help? Any ideas? -al

 

[76Broncofromhell]

Put a 4 core radiator or Chuck's 3 core with a shroud and mechanical fan in there. You will stay at 180 for all time.

 

[NOTPRETTY]

The gears aren't helping that is for sure particularly if you are lugging the engine down. But over heating has many possible sources. I have done just about everything there is that you can do and I still over heat in the same conditions you describe. I haven't tried the 3 core rad from chuck though and might give that a shot. I have the 4 core from WH with a spal fan. I am beginning to think the engine water jackets are done...

Other heating causes:

Timing
No fan shroud
Crappy fan
Rad needs cleaning
Engine is juiced up for HP
Gears
bad water pump
bad or partially functioning thermostat
Bad rad cap
Etc

 

[md_lucky_13]

Another (and much cheaper) option to keep things cooler would be to add an extra cooling fan.

An option you might consider would be the late 80s Subaru GL fan swap. I found mine in a junk yard for $20. It will fit between your core support and grill, and is an easy 2 wire hookup. That would also help things cool down a lot.

Make sure you have a good shroud, and that is probably all you need. You didn't mention what core radiator you had though... If its not a performance 3 core or 4 core, you are wasting time: you will need to upgrade!

Hope that helps!

 

[77pony]

I neglected to mention that I have a 4-core radiator from KBarS. Put it in when I first put the engine in. I use the stock fan and the stock shroud. I think my thermostat is fine, it runs at 170-180 all other times, except when climbing as described. We'll see if the lower gears help, and maybe I'll give an electric fan a try. -al

 

[flousberg]

Have you looked at your water pump pulley, it should be smaller than the crank pulley. If it is the same, you can put on a smaller one and turn the fan and water pump faster at the lower rpms and help in cooling.

 

[77pony]

Thanks. I'll check that pulley. -al

 

[67EB_in_619]

77pony... if you have EFI.. you need a 195* tstat. I replaced mine today and flushed out the radiator. I also got some water wetter (equivalent) and used mainly water in my rad... about 10% coolant.. 90% water. and replaced my rad cap w/ 16# cap and double checked all my overflow lines etc.

It was suggested (by 66horse.. thanks) that I 'burp' the radiator. To do this.. fill it up, take the cap off and start it up. once the tstat opens, it will splash some water out the filler and drop in level.. fill it back up.. this should help get out any air bubbles.

Here is some really interesting info on coolant and its effects on HEATING your engine...

http://www.redlineoil.com/whitePaper/17.pdf

Again.. if you have EFI.. the EEC expects 195* for optimal operating temp... if it isnt there, it will screw with timing and mixture to make you run hotter to try and get it to 195*.

 

[bluesixtynine]

I also share the misery that 77 pony does. I have a 351W with a C-4 , and K-bar-S 4-core radiator that exhibits the same habits. I have tried everthing I know to do with the exception of the aluminum or BC radiator. I also was told that the Windsor has heat pockets on the rear cylinders and tapped the intake manifold to circulate water at the rear. This helped about 5 degrees for a while, but once the rig gets hot, it stays hot.

77pony, to answer your question about gears, I run 4.10's and have the same problem. I run the tranny fluid through the radiator then into a B&M plate style cooler. I figure my next move is to bypass the radiator with the tranny fluid and run a tranny cooler with a fan. Any suggestions where to put this combo? I am running out of room under the hood.

Sorry to get so wordy, but this is a problem I've been dealing with a while.

 

[45acp]

Here is what i did to solve my 351 issues-

1- Watter wetter. This stuff flat out works, period. One of the few "snake oils" on the market that actually does what it says it will do on the bottle. Around $8, and worth $100 if you ask me.

2- Run your water/coolant ratio as low as you can get for your climate. Water transfers heat alot better than coolant. I run mine 75%water, 25%coolant.

3- Cheapo 14" electric fan on front of radiator as a pusher. This add-on will do nothing on the highway, but offroad and slow going helps a ton.

Try 1 and 2 first. If they only help the problem but dont solve it, try #3.

 

[74bronc]

77pony... if you have EFI.. you need a 195* tstat. I replaced mine today and flushed out the radiator. I also got some water wetter (equivalent) and used mainly water in my rad... about 10% coolant.. 90% water. and replaced my rad cap w/ 16# cap and double checked all my overflow lines etc.

It was suggested (by 66horse.. thanks) that I 'burp' the radiator. To do this.. fill it up, take the cap off and start it up. once the tstat opens, it will splash some water out the filler and drop in level.. fill it back up.. this should help get out any air bubbles.

Here is some really interesting info on coolant and its effects on HEATING your engine...

http://www.redlineoil.com/whitePaper/17.pdf

Again.. if you have EFI.. the EEC expects 195* for optimal operating temp... if it isnt there, it will screw with timing and mixture to make you run hotter to try and get it to 195*.

Man, that redline tech info is some good stuff. It was most interesting to me that the WaterWetter, when added to a glycol/water mix, didn't do much in the way of temperature reduction on their Chevy test motor on the dyno but when added to straight water, they got almost 20 degrees reduction in operating temp. I realize that some of this might be marketing hype, but it follows exactly with my experience with WaterWetter. It didn't do too much in my 50/50 mix last summer, but I think I might put it in the bronco with straight water this weekend. Kind of curious now.

 

[elemetal]

I've got a 351W with the same issues but switch to a electric fan and they went away. Remove the regular fan completely, put on one of those spal fans from WH (its a puller, 2700 cfm i think) and put it on a relay. You don't need a shroud cause it attaches directly to the radiator. then make sure you get a temp controller that works off water temp, not the manually adjustable ones that use a tube in the coolant(they suck). I've had this in for over a year and driven 15000 mi with it (NY summers and across the country in July, now in CA) and had no problems. I have a back up fan just in case or if I want peice of mind in the back country.

 

[Unregistered]

Yea, the less coolant you run with the 'wetter the better it works. Guess ill post my home-made test results if it helps-

All testing was done on same day, same trails, August and 100 degrees steady all day

1- morning to lunch- ran 75/25 coolant mix with 195 degree stat. engine temps hovered around 200, would get up to 205-210 on occasional bad long hillclimbs. had to pull over several times and kill the truck/leave the elec. fan running to cool off

2- after lunch, same variables as above. poured in watter wetter only and ran 195 the rest of the day. not once did it get over 195, and it hasnt since then.

Just remember, if you're running a 50/50 mix the watter wetter wont do much. I live down south so there is no reason to run over 75/25 anyway. Running straight water is ok, but plan on replacing water pumps more often as coolant lubricates the pump and inhibits corrosion.

 

[45acp]

ah dammit, that was me above, sorry.

 

[77pony]

Thanks for all the tips. I don't think changing my coolant mixture is gonna work for me. We have winter temps below zero, and it can freeze at night clear into June sometimes and can start again in September (I'm up in the high country), so I'd have to change the coolant in late June and again about Labor day. What a pain. My cooling problems don't only happen in the summer anyway. I'm going to give an electric fan a try, though.

BTW, I'm carbureted, no EFI. -al

 

[HotWheels]

Man, that redline tech info is some good stuff. It was most interesting to me that the WaterWetter, when added to a glycol/water mix, didn't do much in the way of temperature reduction on their Chevy test motor on the dyno but when added to straight water, they got almost 20 degrees reduction in operating temp. I realize that some of this might be marketing hype, but it follows exactly with my experience with WaterWetter. It didn't do too much in my 50/50 mix last summer, but I think I might put it in the bronco with straight water this weekend. Kind of curious now.

Exactly...I used Be Cool + water when i was in hawaii....awesome stuff. I did not even have a shroud.

 

[74bronc]

Thanks for all the tips. I don't think changing my coolant mixture is gonna work for me. We have winter temps below zero, and it can freeze at night clear into June sometimes and can start again in September (I'm up in the high country), so I'd have to change the coolant in late June and again about Labor day. What a pain. My cooling problems don't only happen in the summer anyway. I'm going to give an electric fan a try, though.

BTW, I'm carbureted, no EFI. -al

sorry for off-topic, but what area of Utah are you in?

 

[HotWheels]

try a robert shaw balance thermostat while ur at it.

 

[77pony]

I'm in Wasatch County, an hour SE of SLC. -al

 

[Rustytruck]

If you didn't live in a freeze zone I would bypass the radiator for your tranny cooler. But since you do live in a cold zone make sure you go through the tranny cooler first and then through the radiator. Make sure you have air pulling/pushing through the tranny cooler. If you are not using a 7 blade fan, BC bronco has a really good mechanical fan if it will fit but is noisy as hell. it will pull enough air. I run the factory 7 blade but use a smaller 289 water pump pully but its on a 302 engine. Gearing will help alot and will allow you to kick it in first gear and get the rpms up while going slow thus circulating the coolant much better. with out the proper gearing you dont have enough torque to pull the load so you just build heat in everything. Engine/ exhaust/ coolant /tranny everywhere. The difference is night and day running 4:11 gearing over 3:50 gearing when running 33's everything doesnt have to work so hard so you dont build excess heat in the first place. Especially since you live at altitude you dont get a break like flat landers do. When i fill a coolant system i run with the cap off and the front of the truck up on ramps or a curb so there are no low spots in the engine get, the system hot and full then cap it with a 16 lb cap.