over heating
Senior User
Joined: Dec 2008
Posts: 294
Likes: 0
From: East Bernstadt, Ky
Some vehicles are equipped with air dams and other plastic parts in the front end that allow the vehicle to draw air through the radiator. I don't know know if your truck has these or not but it could be a possiblility if you have removed any plastic. I had a 4x4 s-10 and left the oil filter access panel off of and it would overheat if it got over 45 mph until I put the panel back on. Also it might be the limits of you motor/trans/rear gear setup. My truck would over heat probably if I was going 75mph but i have a 1:1 final ratio on my tranny and 4:10 rear end so I never get over 55.
Freshman User
Joined: Jun 2008
Posts: 41
Likes: 0
ive got an 86 f250 with a 351w 4v and i have/had a simmilar problem. mine is/was due to some bad ported vaccum swiches. the truck would run normal in town but once the temp got up past "m" it would quicly spike to "L" right now ive got the heat riser disconected and some other "valve" in the intake manifold were a choke stove would be dissconected. im going to pick up the parts today after work and as soon as the weather breaks im gonna pop them in. and im gonna clean out the egr valve. ill let you know if it helps.
Lead Driver
Joined: Dec 2002
Posts: 5,491
Likes: 16
From: Kuna ID
Overheating at speed could be a sign of a collapsing lower radiator hose. What is the engine speed at 75mph? You could just be spinning the motor too fast causing extra heat. If I am doing 55mph in my truck in 5th gear, my temp is about 190, if I go the same speed in 4th gear, my temp goes to about 200. It's not hurting anything, it's just extra heat generated from the increased friction.
