Hi All:

I recently installed a new Autometer Temp gauge in my '88 F350 with a 460 after the factory one quit working. Driving around town the temperature is usually between 200 and 210 which seems normal to me (although I can't say I really know what these motors should be running at). The motor has 130,000 miles on it and doesn't burn oil. It has a 5-speed manual tranny.

This weekend while pulling our 2400 lb boat up a couple of mountain passes in 90-100 degree weather I got concerned when the temperature crept up to close to 230. At that point I turned on the heater which quickly brought it down about 15 degrees.

I also noticed that when I restarted the engine after a 15 min stop at a rest area at the top of the mountain pass the temp went up to about 235. Once I got going downhill, the temp quickly dropped to around 210.

When I bought the truck a year ago I had the coolant flushed and the radiator hoses replaced and left it at that. My first question is whether hitting 230 degrees is indicative of a cooling problem or is it "normal" considering the load and the outside temperature?

I'm considering getting a camper for the truck, but don't want to get too ambitious if the engine can't take the load of it plus a boat up and down mountain passes.

I'm also wondering if I would be overreacting if I started replacing cooling system components since I don't know their history (water pump, t-stat, etc)?

Thanks in advance for any advice!

 

I think I would replace teh Tstat if nothing else, and it might not hurt to have the radiator flushed while you have it drained. Yeah 230 is a little on the high side, running at 200-210 is not totally out of range but plenty warm (actually they are more efficent at that temp but if it's climbing higher then I would want to find out why)

 

Most water-cooled internal combustion engines get their hottest (as indicated by the water temp guage) when the engine is shut off and then over the following 15 minutes, just as you noted at the rest stop. This is because the coolant has stopped circulating but the engine is still hot...and so the coolant inside the engine is absorbing a greater amount of heat than if it were circulating.

I don't think that your temperature variation is abnormal; if you are concerned about the temp range at which your engine operates, you may first try a thermostat with a lower temp rating.

Paul

 

I'm with MB, a new thermostat first. But look at the truck carefully. Overheating on the highway can be an airflow problem. Are the radiator fins clean and clear? Do you have a condenser or a stack of coolers in front of the radiator? Fan belt worn or loose?

 

Be sure the antifreeze is not greater than 50/50. I like 40/60 using distilled water, a can of bars leaks and one bottle of watter wetter. New thermostat and radiator cap every couple of years is just good maintenance. Water pumps wear out and if yours is more than 5 or six years old, I'd consider a replacement. Hoses every three or four years, belts the same. And all the stuff the others mentioned. I don't think you have a problem, your truck was just working hard that day.

 

One very important thing not mentioned is the fan clutch. I can attest to the fact (since I have the same setup) that when the 460 fan clutch kicks in, the roar is so loud it overcomes the sound of the engine. Luckily I was warned about it before it happened the first time. The OEM T-stat is 190 degrees I believe. I put a 180 in mine but really didn't notice the difference. On my RV its an E-150 at a 12000 pound load. I believe it's rated for somewhere around 18,000 pounds. I don't know what temp it rises to but on my Ford OEM crap gauge it gets just past the L on NORMAL before the fan clutch kicks in, and the only time I've had it kick in is taking off from dead stops (as was said before, low or no engine speed creates higher engine temps initially) and when I'm travelling in hot weather at 75 mph. Once the clutch engages, it quckly brings the coolant temp down according to the gauge.

I think too you may be OK but I wonder about the clutch as I've heard others have problems with them, but I haven't.

For others reading this, if you must open a hot radiator, keep it running when you open the cap.

 

Thanks for the great advice so far. The fan clutch mentioned by 2000Ford2000 could be an issue. I've never heard anything resembling a roar overcome the noise of the engine. Is there a quick way to tell if it's working correctly?

Thanks again!

 

If it is overheating going slowly or in traffic, the fan clutch might be an issue. If it occurs on the highway, the incoming air is moving faster than the fan could move it anyway with the possible exception of when it is downshifted.

 

Not true Bdox. I've heard my fan kick on while driving 75 mph. The gauge drops quickly when it kicks on. These fans are very efficient and have a lot of power. That's why there's such a roar when it engages. I don't hear it very often. I checked with 2 shops about possibly putting electric fans on the 460, but I was told that there were no combination of fans that could do as well as the Ford OEM. One of the few times Ford did something right.

grantorino: To check the fan clutch, make sure the engine is hot, like when it's 220 or more, stop the engine right away and grab the fan and see if it will turn. It's should be locked pretty tight to the belt. If it turns very free, then that is likely your culprit. What I do is try to spin the fan. If it moves at all when you let go, it's not good enough.

 

I've heard people say that before, but I just find it really hard to believe that a fan pulling air from behind a radiator is going to do better than a 75mph breeze pushing air from the front.

My fan kicks in when I'm driving through town at less than 25mph and have either the A/C on or it's really hot. As soon as I get on the freeway, the fan disengages. I never hear it over about 45mph.

 

Depends on the load. My RV is 6 tons, and at 75 mph, that's a lot of wind resistance. I have noticed it mostly when I've travelled to FL, but it has kicked on in MI on I-94 in the summer and in Nebraska with a high headwind and doing 75. Many times, after driving highway speeds and then stopping for a light or something, it'll kick on just as I start out moving but then fades out after passing 30 mph. I don't like hearing it as I only get 6 mpg normally, and I'm sure it drops the mileage when that fan comes on as I can even feel the pull. on the engine.

 

Sorry 2000, but the clutch fan kicks in as a result of temperature. It's not going to pull in more air through the radiator than running 75mph with a strong headwind unless there is some kind of obstruction like a stack of coolers or the fins being partially blocked by dirt or bugs.

 

Ok, i edited out the first part of this reply, i researched and found out i was wrong, so i removed this part before i had to eat my words ....

i dont know about the airflow on RVs, ive never owned one so i wont act like i know anything about them...but on trucks and cars with frontend radiators, after you go over 40-50 mph the fan isnt doing anything anymore but spinning...like said before at highway speed the wind forcing in from the front is greater than anything a fan can draw in....

my 76 F-150 460 4bbl had an overheating problem that i couldnt find...my engine was heating up over 280* on the highway maxxing out my sunpro guage...i replaced everything trying to fix it with no luck... i never really had any issues the whole time it did this because i had new hoses, and thats what you have to worry about most when over heating....after two years i finally tore down the engine and discovered my water passages where blocked with radiator sealer (bars stopleak)...i cleared it out and the major overheating is gone....every now and then my motor still hits 230-240, but mostly sits right at 210 where its supposed to be...heck, my wifes new Jeep sits at 210 so im sure these big ol motors are pumping out just as much heat if not more, hence the large radiators...so as long as you have good hoses and such i wouldnt worry about 230* here and there under load, i had a radiator dealer tell me that 460's where designed to handle highload temps around 250*, anything over that for extended periods of time is when you have to worry about head gaskets and radiators going out...as for running temps, 200-210 is ideal, my truck used to run at 195*, but i havent been able to get it back down that low yet....

 

I think part of the problem is runing a 195+degre thermostat. You don't have the reserve in the cooling capasety. Something else to look for is dirt and trash in the radiator along with bent fins. I have ben in San Antoio when the lake flyes were hatching in the spring "mostley east between Housten and SA" and seen cars boiling over because of the lake flys cloging the radiator. I don't think this is your main problem but it woulden't hurt to wash out your radiator from the back side.
Good luck
Bill

 

All I can tell you is what I have seen. I've seen it happen several times in my 88 Jayco E-350 RV with 460. There is no obstructions other than this engine packs in tight in a van. Much more so than in a pickup, so maybe that's why it happens on my RV.