Long time member on the digest list, 1st time on the message boards.
I bought a 78 Bronco 351 C6 on my way home from northern MN (in-laws). I just had my nephew try to drive it 300 mi to my place in the Twin Cities. It made it 30 mi and started overheating, temp gauge didn't work and he didn't catch it till the steam came.

This Bronco has a 7 1/2 ft plow on it and it was about 40 degrees out. Should this vehicle be able to handle having the plow on and blocking the airflow and drive without over heating? I am wondering is all I have to do is go up and take the plow off and drive it home or is this a sign of a bigger problem?

On the temp gauge........the gas gauge works and there is no oil gauge (just idiot light) so is this likely the sending unit or wiring or could it still be the IVR? thing?

Sorry for the long post, any help is appreciated. I am driving up north tomorrow to try to rescue it.

David in MN.

 

With my experience, the engine needs all the airflow it can get. I have a 79 with a 351m and it will run noticeably hotter if I even take the fan shroud off. If the plow is really blocking the flow of air, then you may need an electric fan on the front of the radiator when plowing, but I would check some other things first. Change the thermostat and you might want to have the radiator flushed. I would replace the gauge too either with a warning light or another gauge as overheating can be pretty serious. Good luck getting things to cool down.

 

I am talking about when just driving down the road, not while plowing (just trying to get it home not do any work yet) :=)). Anyone out there with a plow on there truck have trouble with it overheating in highway driving?

Thanks,

 

Drjohn,
I am a former Truck & Bus engineer and have worked on plow projects in the past. Cooling is the primary research concern on these type projects. Most cooling problems occur when the plow is down. If your truck is overheating when the plow is up then you probably have another problem.
Here's a quicky for you. Check your trans fluid. Strangely enough, if the trans fluid is low and the tranny is slipping it will overheat in about thirty miles. Now comes the trick, what kind of trans fluid are you running? Don't mix! Your two choices are Type F or Dextron III. I've got a 78 F150 with a 351M/C6 and it works better/cooler on Type F. I never did figure what was recommended?
Secondly, Look for water in your oil. You have described the worst case overheat and you may pay dearly for driving without a temp gauge.
Thirdly, a sending temp unit is worth about $5 and is located on the front of the block to the passenger's side. Ground your sending unit wire and see if the gauge moves. Do not ground the wire for more than 5 seconds.
Fourthly, Feel your upper radiator hose for heat to see if the thermostat is open or not.
Good Luck,Have Fun
KingFisher

 

Check the thermostat. You should be able to pull a house trailer at 40 degrees and not have a problem.


Bear