Engine Overheating, PLEASE HELP!

[Elmobile]

I have been having problems recently with my 1988 Bronco II. It doesn't matter what the outside condtions are when this happens. The temperature gauge will read higher than normal and will max completly out to hot (overheat) on multiple occasions during short drives (less than 20 minutes or 15 miles). It will even do this several times idiling in a parking lot when the outside temperature is below freezing. The vehicle doesn't seem to be overheating, no expansion into the coolant resevoir etc, and the engine didn't blow when I ran it anyway for a minute or two in the red. The gauge will max out, then a second or two later will return to relatively normal. I took it to the mechanic, who put in a brand new radiator, water pump, power steering pump, and hoses. I have flushed the coolant and have not observed any bubbles, contaminants, or leaks anywhere on multiple occasions. I have gone through three thermostats and I now use a 160 degree thermostat. I have replaced the temperature sending unit sensor that reads the temperature multiple times. I have completly run out of ideas and things to replace short of the gauge itself. This vehicle basically has a whole new cooling system and I have put well over $1,000 into fixing this problem. I recently bypassed the entire temperature gauge system to find out if it is the engine or if its the gauge. The mechanical gauge I used showed no abnormalities and consistanly stayed at 160 degrees like the thermostate was suposed keep it at. I think the gauge is the problem. However, no one carries a replacement temperature gauge anymore. Is there anyone who can tell me if it could be something else or if there is a way to test this electrical gauge "electronically", measuring the electrical resistance maybe. If so how many ohms is it supposed to read. I would really appreciate if anyone could help me with this extremly expensive and irritating problem.

 

[RangerMan64]

Have you tried to get a replacement at an auto salvage yard? I bet you could pick one up for $5

 

[86freebie]

my 86 will go from normal(middle) on a hot or cold day and jump to running hot. i replaced thermostat, radiator cap, all the hoses, flushed the radiator all my self. talked to a local car "god" at Napa and was told most newer vehicles have a rheostat on the back of the instrument cluster that is usually the problem. he said go mechanical or pull over every 5 miles and stick a meat thermomator in the cap.

 

[Hardwareman]

Sounds like your engine's operating normally and you just want your factory gauge to function properly. You'll probably have to get another gauge from a junkyard/ebay like posted above.




Allen

 

[MAKG]

Are your OTHER gauges changing as well? Especially, oil pressure should have exactly two positions -- zero and normal. Any other variation is an electrical system problem.

As electrical gauges often are, yours may be functioning as an electrical system meter, telling you you have a problem with voltage regulation.

The only RIGHT way to do this is with a calibrated mechanical gauge, permanently mounted in the vehicle.

And something is odd if you aren't seeing the 160 deg cycle. A mechanical gauge should be fast enough to see that the opening and closing temperatures aren't the same.

Remove that 160 deg ASAP as it will plug your cat long term. You'll keep the computer continuously in warm-up mode. Stock is 195 deg, and there really is no reason to go lower (no, it doesn't improve cooling capacity -- an open thermostat is an open thermostat).

 

[86freebie]

Remove that 160 deg ASAP as it will plug your cat long term. You'll keep the computer continuously in warm-up mode. Stock is 195 deg, and there really is no reason to go lower (no, it doesn't improve cooling capacity -- an open thermostat is an open thermostat).

i tried a 180 degree thermostat because "colder engine=more power" crock of crap in my case. i have a small mountain between work and home, and with the 195 degree stat i can pull it at about 62. with the 180 i had to down shift more. maybe in my head.

 

[mhagedon]

I'm having the same problem so I'd really like to know if anyone has a solution! Although the coolant temp usually stays at the "M" in normal it does spike on occasion. I was actually going to post a thread but i saw this one and figured it'd fit right in.

My gas gauge is stuck between the empty line and 1/4 tank. It will sometimes sink below empty and then rise slowly back up. It should read above 1/4 as i just put in my last $20 (about 5 gallons of iowa ethanol) When I have enough money to fill it up it buries the gauge past full like it should. I had the same problem on my '88 BII. I was thinking i had a bad sending unit.. But i thought I'd check here for some tips first before i go tearing apart my daily driver!

Thanks

 

[RangerMan64]

Well mhagedon,
I have the same symptoms that you have regarding temp. I believe it is overheating because the truck always seemed to be cold blooded as it would stay below the L. But now it goes to the A and often fluctuates.
Now regarding your gas gauge, I have no idea why your gauge sinks below empty and then raises back up. I would say though never go below a 1/4 tank. I have done this and every time I have I end up getting a clogged fuel filter.
I have a question for you though, why does my gauge always go past full when I fill up?

 

[mhagedon]

Well both of my 2.3's always ran at the "M" and the 2.9 in my BII did fluctuate alot and ran alot hotter than i thought it should've. But since there aren't any numbers on the gauge i never knew how hot normal was! And the gauge in my T bird quit going past the blue line after a while. Anyways get a different gauge to check this out.

As for the gas gauge, i'm still lost. It's annoying as hell. I'm just counting miles! But when the tank is full the gauge goes to it's full travel. That's how all fords are i'm thinking.

 

[derek54401]

as for the overheating, when I was relying on the stock gauge, my 2.9 would "overheat" all the time, but the coolant never overflowed into the resivoir. now with a sunpro mechanical gauge (picked up a set with oil press, temp, and voltage for like $25 at autozone) the gauge stays glued at about 185 all the time. sometimes when idling in a parking lot with the a/c on, on a hot summer day the temp does climb, but never over 205. i can only conclude that the stock gauge has a very narrow range of temps that it can display, and that the very top of it is about 210. keep in mind that thermostats will start to open 10-20 deg. before their set temp, and will be fully open at the stated temp. also, when replacing your thermostat, ensure that your new t-stat will not be "fighting" your fan clutch - the thermostat should not be closing to heat the engine up while your fan clutch is trying to engage and cool the engine down. that is why, when idling, the temp may climb to the fan clutch engagement temp.


as for the fuel gauge, i believe all fords read well above F when full. my ranger does this, so does my expedition (hardly ever fill that up, with a 36 gal. tank)

 

[MAKG]

i tried a 180 degree thermostat because "colder engine=more power" crock of crap in my case. i have a small mountain between work and home, and with the 195 degree stat i can pull it at about 62. with the 180 i had to down shift more. maybe in my head.

Which mountain?

I used to drive Hwy 17 in a 1986 Bronco II with a 2.9L and 1/4 million miles.

No problem, as long as I didn't absolutely insist on doing it in 5th gear.

 

[86freebie]

hwy 80 leaving cordelia to vallejo. i live suisun and work novato. 5 days a week. not bad though. just did the math and i have put about 120000 miles just since we bought the house.

 

[MAKG]

That's not a serious mountain at all. You have a problem with that truck.

I took the Bronco II through there on almost every roadtrip. No problem at (or above) the 65 MPH speed limit.

 

[86freebie]

i have a small mountain between work and home

:icon_confused:

220000 miles on her. 32x11.5. 3.73 gears. and only a 2.9l.

i did say "small"
if i am at 65 i get through the little steep part at about 60 in 5th. any slower and i have to downshift to get speed back or i will drop into the high 40's :nopityA:

would not trade it for anything other than another first gen ranger.

 

[MAKG]

Why are you insisting on staying in 5th? 5th sucks on FM145s anyway.

You redline at 5500 RPM. Take advantage of that. NEVER run a 2.9L below 2000 RPM unless you're idling at a red light.

I drove my Bronco II over the Eisenhower Tunnel (11,000 feet) at 70 MPH in 3rd gear uphill. Drive it how it needs, not how you want it to be.

I had 29 inch tires. The extra 10% matters, but not nearly as much as you would need to explain the effect at hand. It also had over 200,000 miles at the time.

And I still got 20 MPG on that trip.

 

[86freebie]

driving it like that gets me 14.5 to 16 miles to the gallon. true miles not uncalibrated bigger tires reading. if i start driving it, like it can be driven i will drop into 11 miles to the gallon. my contour has 167000 miles on it that are hard miles. my mustang had 117000 miles and most of those are probably above 4500 on the tach. i do know how to rev-em-up
contour got 30+ mpg. step daughter totalled it a month ago
stang got 17ish. sold it to get this truck.

i dont insist but with a 15 gallon tank (safety buffer=14 gallon) thats only 2.5 days driving before fill up. it gets old. and at 11 mpg that would be a fill up every 2 days. my bank would cancel my atm/visa.

 

[95' Ranger SS]

I cant seem to figure out why. but my temperature gauge doesnot work. I put a new thermostat in it and gasket. and i know its overheating becuase A. the headgasket is leaking. B. i can smell the antifreeze when im driving after the engine is fully warmed up.

 

[MAKG]

You can have leaks and antifreeze smells on a cold engine. It doesn't mean you are overheating.

And an overheat isn't the only way to make the heads crack on 2.9Ls (though it does help).