94 ranger 3.0 overheating

[DRIFTGOD187]

i bought this truck last year and never had heat or a overheating problem.

this year i decided to change the heater core and i got nice hot air instantly.

that is until about 2 days later when i was driving to work and the defrost starting blowing cold air, it was hot and then cold.

the next day i was driving to work and it did it again, this time i was watching the temp gauge and noticed when the heat got cold the temp gauge got hot.

could this be a thermostat or temp sensor problem ???

i had the coolant system flushed and it still does the same thing.

any help would be greatly appreciated.

 

[JohnnyO]

In order of likelyhood:
Heater control valve. Would explain the lack of heat but not the overheating.
Stuck thermostat.
The water pump took a powder.
Worst case, blown head gasket. When my Lincoln had the same symptoms you describe, it was a head gasket. Sorry.

 

[DRIFTGOD187]

dang, i hope its not a head gasket

 

[DRIFTGOD187]

if it is a head gasket how hard is it to replace ??? should i pull the engine and if i do should i just change engines ???

 

[JohnnyO]

Head gaskets can be done in the vehicle. Frankly it is beyond the scope of my ability and tool collection. No need to change the whole engine. If it is the head gasket(s), change the oil too before you start it up. Maybe change the oil right now just to get a look at it. IF you see water in it or if it is a muddy brown color and not clean or black, then there is water in the oil and it is the head gasket.

 

[DRIFTGOD187]

ok i know this is going to make no sense at all, but i decided to change the thermostat. one bolt came out and the other broke off in the intake !!! i then decided to just tighten it back up so i wouldnt break the seal, and now it leaks lol. here is the part that doesnt make sense to me, i now have heat and the truck hasnt over heated yet ???

as far as the oil goes, it leaks a little oil and the oil on the groung looks/smells like new oil. i just had the coolant flushed and the oil changed less than 100 miles ago.

 

[JohnnyO]

here is the part that doesnt make sense to me, i now have heat and the truck hasnt over heated yet ???

No, that makes perfect sense if everything is working properly.
Then it sounds like the problem was the thermostat.

The JohnnyO Scientific Method As Applied To Vehicles:
1. Identify the problem.
2. List possible solutions to the problem.
3. Begin with the cheapest alternative and work up from there.

Good luck with the bolt.

 

[DRIFTGOD187]

Good luck with the bolt.

i was lucky and got the bolt out with vice-grips







now i just have to wait until monday to get a bolt from the local junk yard

 

[DRIFTGOD187]

i ended up taking the good bolt to the local central tractor and found a metric nut to fit it, then bought 2 new bolts that size.

 

[DRIFTGOD187]

Head gaskets can be done in the vehicle. Frankly it is beyond the scope of my ability and tool collection. No need to change the whole engine. If it is the head gasket(s), change the oil too before you start it up. Maybe change the oil right now just to get a look at it. IF you see water in it or if it is a muddy brown color and not clean or black, then there is water in the oil and it is the head gasket.

i was driving home from work last week and it started running bad and overheated, when i got home water was pouring out of the exhaust and the oil was full of water. im pulling the heads off tomorow.