overheating

[77pony]

Turns out my water pump pulley is the same size as the crankshaft pulley. I don't know if this pulley was from the original 302 or the 351W I pulled out of a '69 Cougar. Can anybody advise me how to go about getting a smaller diameter pulley? JBG has them for 289/302. -al

 

[74bronc]

I have had a problem with my 67 EB with overheating too. I have a 71 351W that is 60 over with a mild cam, flow cooler water pump, 4 core radiator and a seperate tranny cooler on the passenger fender well. Before I had it rebuilt it would never get above 190F, since I have it rebuilt I can drive it all day on the road but once I stop and let it idle it climbs to 200-210 in a heartbeat. It has a smaller water pump pulley, fan shroud that is fit properly but only overheats after it has been driven for a while. I messed with the timing and that seems to not have made a difference. The cap has been changed and the thermostat has been changed a few times. I now have a 160F thermostat in it thinking that it might make a difference so far it has not. Any suggestions?

If you are running coolant, I would dilute it out with distilled water. Next, .060 overbore is the absolute max on a SBF and it is entirely possible that the overbore is contributing to your warm running problem. Does it ever get hotter than 200-210? That is hardly "overheating" on these engines. I wouldn't get too concerned until closer to 220. A tigher engine will always run warmer than an old, well broken in (or worn out) motor. My 351W runs cooler and cooler all the time. If you have a chain parts store el cheapo thermostat in it, I would change it out in favor of a balanced thermostat. you might not be taking full advantage of your flow kooler high flow pump. A common misconception is that a cooler thermostat will make the engine run cooler when in reality it will only take the engine longer to warm up and eventually overheat.

 

[unregistered]

Well I had the engine rebuilt by a race engine builder in town and we have talked on many occasions about my problem. He said when he rebuilt the engine that the 60 over should not be the problem (he said there should be plenty of water jackets left) He is very reputable. After the temp starts climbing if I start moving again the temps go right down real quick to normal. I have autometer gauges, not the stock anymore. I still only have about about 2500 miles on the engine. I have been deployed to much to the desert, so not much EB fun at all the past two summers. It has gone to 220F a few times that's when it gets shut down to cool down. I had the stock seven blade on the engine, then I swaped it out with a flex fan from BC Bronco's. That thing really sucks some air through it. I can put a terry cloth towel in front of the grill and it will keep it stuck to the grill from the suction. I have a bottle of water weeter but have not used it yet, I figured it should not overheat without, so wouldn't that be masking a bigger problem if it works? So where would I get a better thermostat, Jegs summit etc? I have a decent mix of coolant and water, you need coolant in North Dakota in the winter. I hope this explains things somewhat better.

 

[HotWheels]

Robert Shaw makes the best thermostat in the business. I believe they are available from Jegs/Summit. I got mine from Performanceunlimited.com.

hth,

Mick

 

[Bronco Ben]

this post has been edited after reading all the post by 77!


Are you running the transmission cooler from the radiator? this could cause part of the problem, I doubt that the coolant mixture is a problem, or the fan. I'd say its a clogged radiator or bad hose, the hose could be colaspeing and cutting down on your coolant flow. WIth it warm turn off the engine and feel the bottem of your radiator, if its a different temp than the say "middle" or "top" you could have some plugging in your radiator. If you've ddriven it for two years like this i dont know if a thermostat would be your problem, unless like someone stated above its to low a temp thermostat. Try a new themostat, 185 or hotter, and undo your bottem radiator hose, with a garden hose (on) filling your radiator. let it pour out the bottem while the engine is running, until you hear or see your thermostat cycle several times! That is a way I test my thermostat, and check to see what all is in the bottem of my radiator. hope this helps
Bronco Ben

 

[74bronc]

Since you don't have a problem going down the road, that means that you have an airflow problem at slow speeds. You could also have some problems getting hot air out of the engine compartment. I would start by adding an aux fan to the front of your radiator and see if that does anything. 2500 miles is still not alot of miles on an engine and I would expect it to still run a little warm. I would still change over to straight water and water wetter for the summer and then go back to coolant in the fall (or whenever you start to have freezing temps). Anyone that knows SBF's knows that a .060 overbore is pushing it. Every machinist that I have talked to have told me they won't even do it (.040 max). Not trying to pee on your parade or your engine builder, but this is what I have been told by many different machinsts.

 

[CC135_inND]

Bronco Ben

havent read all these post but if its running hot there can only be one of these problems
1)radiator is clogged up
2)thermostat is bad or wrong
3)head gaskets are blown or are installed backwards blocking the coolant holes.........this shouldnt be it!
4)colasping radiator hoses
5)water pump impeller is turning wrong way or water pump is bad
6)water jackets are clogged somhow.
7)cracked heads
8)cracked block


Well now that I am at home I can sign on. The radiator was bought from JBG when I got the engine rebuilt. I had it gone through at a shop after I nicked it with the fan at SOB in OR a couple of years ago. The shop said that the radiator is good to go. The thermostat is from NAPA, I can order a good one if that is the problem, should I go with a 180F T-stat? It shouldn't be the head gaskets. Hoses both top and bottom have the wire in them. Water pump is the right one ordered from Summit (flow kooler). No water in oil or vice versa. The engine was all checked when rebuilt. It has the new product heads on it now (brand new out of box). It will sit in the driveway idling for a long time at normal temps, it only climbs when I have been driving and then let it sit. One of the other chages that I did after the rebuild was add L&L Headers. But I wouldn't think that that would make a difference? Thanks for the sugestions.

 

[hmgoy]

also if your radiator has the tranny cooler in it you may want to put an extra tranny coole in or totaly separate the tranny cooler from the radiatior. this will releive the radiators job of cooling both the engine and the tranny it will be able to cool only the engine. that will help a bit

 

[CC135_inND]

I installed a seperate tranny cooler with fan on the passengers fender from BC Broncos. When I did that I took it completely out of the radiator. I thought that might be soom of the problem, the tranny temps are good. But it did'nt seem to help much with the hot tranny fluid out of the picture.

 

[Bronco Ben]

i jump post sometimes, and I went back and read all the post (well all of yours ) and edited my post. Did you say you have an external stand alone trans cooler??? if not try that it will definetly help!
Bronco Ben

 

[Bronco Ben]

dude your quick! lol

thats hard to say, the .060 overbore could be a contributor, but I'm not really sure I've heard the same things that the others have posted about it generating more heat with a larger overbore but have never experienced this myself so I cant comment much on it!

from what all you say everything seems to be in order, only other thing I can think of is maybe a bad hose as stated above, or maybe one of your water jackets is partically plugged or maybe you could have your timing checked, I've heard of to high of timing causing problems like overheating.....thats all I can think of for now, hope one of these suggestions helps!
Bronco Ben

 

[Bronco Ben]

oh also an additional electric pusher fan definetly wont hurt!

 

[CC135_inND]

I appreciate the help, now all I have to do is find some time to experiment. I will try the T-Stat and maybe a new radiator cap. I know the hoses are all good. They were all replaced when the engine was put in. I have been kicking around the idea of a pusher fan too. With the gas at $2.00 a gallon for the good stuff and $1.87 for the cheap stuff this could be an expensive summer. I guess it's only money you can't take it with ya. %)

 

[Bronco Ben]

yep I payed $1.81.9 a gallon this morning, and I drive 74 miles round trip to work. Its a good thing i have a little work car that gets 32mpg or I'd die!
Bronco Ben

 

[brianlr7773]

Some things to try

Ok Lots of good items to check have been posted and I though I would throw my 2 cents into it as well. I had the EXACT SAME issue with 2 broncos and this is the steps i did to correct it.

Oh and i am in vegas where it is well over 100 most of the time and my broncos never overheat or even go past 3/4's on the gauge while at a standstill in crazy gridlock or on a trail.

I run a stock water pump, 3 core james duff radiator / stock shroud and a 18inch flex fan with no cluctch

1 ) make sure to run a 180 thermostat, Drill a very small hole in the top of the thermostat to help the engine bleed air off from inside the block,

2) make sure , if you are running an aftermarket intake that it actually has rear cooling crossover passages in it (many DONT) therefor it wont be able to circulate through the heads,

3) Radiator, you have that solved...

4) water pump, if it works then thats all there is to it... you dont need a expensive ass waterpump I use stock

5) use a 70/30 coolent mix

6) make sure to dump the orginal fan, get a 18inch flex fan and possibly not use a clutch on it. MAKE sure to use a shroud or else it wont pull enough air through the radiator

6) ABSOLUTLY the most important thing that you can ever do... HAVE THE ENGINE COOLING HOOKED TO A VACUMM TO PURGE THE AIR.. the way the engines tilt in the bronco traps air and is about impossible to get out just by burping the radiator unless u try it on a very steep hill or something. This more often then not is the major reasons they overheat or run way to warm, I have helped many fellow bronco guys with the same problem and just the thermostat and the vacumm to purge solved there problems...

Hope this helps.

 

[Sac '68 sport]

Why, and where do you drill the thermostat?
Got a pic you could put up?

Thanks

 

[Rustytruck]

Go to a radiator shop and get the system pressure checked. if it wont hold pressure you will over heat. if it continues to build pressure you have a leaky head gaskit. If the over bore was a problem then it would over heat at mid speed not at idle with no load. I like the idea of the vacuum purge first I've ever heard of it and a damn smart idea. Learn something every day. A few years ago I thought I had a cooling problem and it turned out to be a minor leak in the old head gaskits compression was slowly leaking in the cooling system and over filling the over flow bottle and dumping coolant. It would only do this when fully warmed up and as soon as you got off the freeway and stopped the system would simulate boiling over. So watch out for leaking head gaskits.

 

[Rustytruck]

I am concerned about everyones understanding of fan cfm.
for the sake of argument an 8 inch fan pulls 800 cfm and you mount this fan right up against the radiator like alot of people do. you get 800 cfm pulling/pushing through an 8 inch circle. to get the same flow in a 12 inch fan covering a 12 inch area you must pull slightly over 1600 cfm to move the same amount of air per square inch of the surface the 12 inch fan covers. now if you mount a 16 inch fan right up against it the fan will have to pull twice the amount again or 3200 cfm to move the same amount of air through the same amout of square inches the 16 inch fan covers. Only in the application where the fan is shrouded and the whole radiator flows through the 8,12,16 inch fan will you really see much of an increase in cooling power when you up the cfm flow. Performance cars running electric fans build them into a fan shroud so the whole surface of the radiator gets sucked through dual fans and not just mount the fans flush to the surface so air only pushes/pulls just the fan Diameter. So just buying an 8 inch pusher fan at 600 cfm or buying an 8 inch fan at 1200 cfm may not get you any more cooling power if the fans are not applied properly.

 

[flousberg]

Turns out my water pump pulley is the same size as the crankshaft pulley. I don't know if this pulley was from the original 302 or the 351W I pulled out of a '69 Cougar. Can anybody advise me how to go about getting a smaller diameter pulley? JBG has them for 289/302. -al

I also need to find a new pulley.

 

[NOTPRETTY]

I posted early and now have caught up. Great info out there. I have a couple questions...

Chuck...Questions...

I have the spal 16" fan...Noisy as hell...Is your 7 blade mechanical fan loud like was posted earlier. The noise of the spal is driving me to change as much as the heat issue.

I have a 4 core staggered WH rad with the spal with no shroud. I do get hot on the highway, but it is not nearly as bad as crawling long steady hills. I have the same problem as the original post states. But get this, I was over heating on a snow run with the temp out at 20 degrees. When I say over heating I was hitting 220- 225. I even put snow on the top of the rad. I was working the enigine damn hard...up hill slipping and sliding etc. Anyway, I will check your 11 listed items first. I will also add the 2 inch body lift plate for better air flow. But, I want to get back to a mechanical fan and was thinking of your 7 blade. Long way to get to this question, but what shroud have you found works best...stock? How big in diameter is the 7 blade fan. Does it fit in the stock shroud?

Also, was thinking of putting a fan in front to assist like you said. Does the spal push...I don't know and thought you might know. Just reverse the hot wire???

Also a bit of info for everyone. I found a cheap aluminum rad at summit that looks like it would work in an EB...I am not recommending it or endorsing it, but the price was good and is about the right size. I know other EBer's which have installed it, but have no feedback at all. Anyone?? NON Epoxy HOWE RAD FOR $199.00. Might need to fab a bit, but much cheaper.

summit

Part number: HRE-342A Chuck any opinions on it?