Engine Temp Problem
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Senior User
Joined: Dec 2005
Posts: 253
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From: Beaver, Pennsylvania
Engine Temp Problem
I have a "94" Ranger 4.0 with 183,000 miles. Problem I'm having started after the water pump went out. After replacing the pump the temp gauge started out ok, got some heat, then the gauge would go close to hot and start down slow. I made sure i purged all air. then replaced thermostate 2X with same results. Not loosing any fluid, removed hoses from heater core to make sure all air was out.
I also replaced heater core & installed a flush kit, still the same problem. I also changed the pump AGAIN, still the same. This is driving me nuts, the engine seems to be running cold except for when the gauge shoots up, mostly when I come to a stop, & some times while driving, not all the way too hot but close then drops to COLD & the cycle starts all over. When its cold out the cycle is slower but the gauge drops all the way to cold & I start loosing heat.
Any help or suggestions would be great! Thanks
I also replaced heater core & installed a flush kit, still the same problem. I also changed the pump AGAIN, still the same. This is driving me nuts, the engine seems to be running cold except for when the gauge shoots up, mostly when I come to a stop, & some times while driving, not all the way too hot but close then drops to COLD & the cycle starts all over. When its cold out the cycle is slower but the gauge drops all the way to cold & I start loosing heat.
Any help or suggestions would be great! Thanks
Postmaster
Joined: Oct 2003
Posts: 4,516
Likes: 1
From: SoCal
I've read that the same engine can take 2 different pumps. With a multi belt engine the pump turns clockwise, but with a serpentine the pump turns counter clockwise.
Might want to check with a Ford dealer & see if there are different part numbers for 4.0 pumps.
Might want to check with a Ford dealer & see if there are different part numbers for 4.0 pumps.
Post Fiend
Joined: Feb 2003
Posts: 6,940
Likes: 2
From: Eastern WA
Most likely causes:
*Bad temp gauge sending unit
*Bad thermostat.
*There is a very remote chance that the gauge or wiring are bad but I'd move this to the bottom of the list.
I bought a 94 with a 4.0 new; in it's 11 year life it ate about four temp gauge senders. I also found that when replacing a thermostat it was smart to replace the sender at the same time. I always used OEM parts as I wanted to produce the same desired result that a Ford service department would want to present to a paying customer. On the thermostat, make sure the bleed hole is at the 12o'clock position. I will assume that you didn't install the thermostat backwards
.
*Bad temp gauge sending unit
*Bad thermostat.
*There is a very remote chance that the gauge or wiring are bad but I'd move this to the bottom of the list.
I bought a 94 with a 4.0 new; in it's 11 year life it ate about four temp gauge senders. I also found that when replacing a thermostat it was smart to replace the sender at the same time. I always used OEM parts as I wanted to produce the same desired result that a Ford service department would want to present to a paying customer. On the thermostat, make sure the bleed hole is at the 12o'clock position. I will assume that you didn't install the thermostat backwards
.
Postmaster
Joined: Aug 2003
Posts: 2,873
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From: St. Peter
It sounds like all of the air isnt purged out since you say it happens alot when you stop. How is your radiator cap? Have you replaced that at all? also there are 2 sensors. 1 is the sending unit for the gauge on the dash, and the other is the sensor for the computer. The one for the gauge on the dash has 1 wire, make sure thats the one your replacing. The 2 wire one is for the computer, and wont have any effect on the dash gauge. Also, inspect the lines from your radiator to your overflow coolant tank, make sure everything is nice and tight, and also make sure there is sufficent coolant in the overflow tank too. You might want to have your coolant system pressure tested too. This will tell you if there are any places coolant is escaping like into the heads/combustion chamber, etc. Most of these testers can test your radiator cap too. good luck, let us know, and welcome to FTE!
Thread Starter
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Senior User
Joined: Dec 2005
Posts: 253
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From: Beaver, Pennsylvania
I have replaced Rad, cap sensor for gauge. Now I didn't know there are 2 different pumps for a 4.0! Since the problem started after I replaced the pump I am going to have to check into that. As the engine is warming up the coolent does not seem to want to circulate until the stat, opens fully building up alot of pressure then quick movement, with quik cool down. and the colder the weather the worse it gets. as the guage moves toward high normal I get heat then it drops all the way to COLD and I lose heat for a couple minuts until the cycle starts again. I replaced stat, 2x the bleeder is up, spring toward the intake. It just seem like it is exchanging water between rad & engine instead of constant circulation.
Postmaster
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From: St. Peter
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Freshman User
Joined: Nov 2004
Posts: 35
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From: Greenville, In.
Originally Posted by Rags
I have replaced Rad, cap sensor for gauge. Now I didn't know there are 2 different pumps for a 4.0! Since the problem started after I replaced the pump I am going to have to check into that. As the engine is warming up the coolent does not seem to want to circulate until the stat, opens fully building up alot of pressure then quick movement, with quik cool down. and the colder the weather the worse it gets. as the guage moves toward high normal I get heat then it drops all the way to COLD and I lose heat for a couple minuts until the cycle starts again. I replaced stat, 2x the bleeder is up, spring toward the intake. It just seem like it is exchanging water between rad & engine instead of constant circulation.
Don't know about a 4.0 but on some engines you can trap an air bubble under the sending unit when you refill the radiator. This can cause your symptoms. If you suspect it, loosen the sender almost all the way with the engine running and the radiator cap OFF! This will bleed the air out.
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