need thermostat help...

[gijoecam]

93 Ranger 4x4, 4.0 auto. Replaced the radiator last weekend, so I did the hoses and thermostat too. (Looked like the "core" in the side of the radiator had broken loose, causing a temp rise at idle... oh, and it leaked) When I reinstalled the t'stat, I put the little check-ball facing up... was it supposed to be down? I'm still having an odd temperature problem... at steady state (idle or cruising on the freeway, makes no difference) the temp creeps up to the space beteween the R and the M, then drifts back down to the left edge of the N... I can't imagine that the thermal cycling is doing the engine any good (especially at 150,000 miles) but could this be caused by the t'stat being upside down? I need to pull it back apart anyhow... didn't get a good seal on the elbow and it's leaking on me...


Update:
OK, here's the scoop... I pulled it apart last night and found a couple of things...

1) Apparently when I installed the housing, I knocked the 'stat out of position. I managed to pinch the gasket between the housing and the head... hence, the leak.

2) The t'stat was in with the vent hole up... scratch that idea.

3) That third bolt is a pain in the butt to get started (the one behind the tensioner... I really don't want to do this again... any ideas?

4) Lower intake manifold gasket? I've been reading about it here... maybe?

I've got a couple ideas... maybe the water pump? I would think that it would only be a problem if the belt was slipping (which it isn't)

Sending Unit? Maybe the temp is just fine, but the sending unit for the gauge is whacked?

I can't figure it out... I'm stumped. Any ideas?

-Joe-

 

[TPLYNCH]

Replace your radiator cap..... It may not be able to hold the pressure now that you've replaced everything and the system isn't leaking........

 

[Rfidd]

I have been fighting this with my 92 since I swapped the engine last november. I am not a mechanic, but I guess since I swapped the engine myself, I could be some kinda monkey wrench or something. I think I may have mine fixed but time will tell.
IMO what is going on with the temperature guage I believe is air getting into your system. The comment about the radiator cap is good since a bad one might allow air to leak into the system. The air that gets into the system apparently accumulates near the temperature sending unit, which looks located at the highest spot in the engine. The air bubble rolls around there and messes with the temperature guage like crazy. I think the low temp is when the air pocket is hovering around the sending unit, and the higher temp is when you have fluid there. If we had an idiot light we wouldn't know about it.
So how does air get there? Maybe a bad radiator cap, I have read here, that that sometimes heals the EX. Maybe a head gasket, leaking exhaust. In my case I think when I replaced the engine I used the same cheap hose clamps that were on the damn thing when it come out. Last weekend my son and I replaced those with screw type hose clamps, and I think I am seeing some remedy. I would recommend replacing them all if you haven't already.
Sorry for being so longwinded, but I have been thinking about this a long time.
Good luck, Rick

 

[Triton46]

Is there a particular radiator cap that needs to be used (pressure)? I am getting an 'active' temp guage myself. I recently replaced all the hoses and radiator fluid. A new stat and radiator were put in one year ago, however I used the old radiator cap.

My temp ranges between N and M when warming up and O and A from 20min until I reach my destination (total commute is 60min).

 

[JamminG4Jim]

You all may have thought of this already, but I thought i'd throw it out here for ya.

I had a cooling fan clutch go bad on me, and before i replaced it the temp gauge would range all over the place.

Hope this helps.

Jim

 

[ol_ben]

I am on my fourth t-stat and third heater core in my 93 xlt. The first t-stat stuck shut and overheated. Then the heater core leaked. I replaced the thermostat and heater core The T-stat fluctuated wildly and never got any meaningful heat. I eventually replaced the t-stat again and still hed the fluctuations and little heat.
Both t-stats and the heater core were after market brands purchased at a local auto parts. a couple of weeks ago I went to the ford dealer and bought original ford heater core and t-stat. the ford heater core was obviously heavier than the aftermarket one with more tubes and fins but cost 4 times as much.
After installing the new heater core and thermostat I finally have good heat (its been 2 years). The t-stat does not fluctuate. It comes to about between the O and R and stays.

based on these experiences I would recommend to purchase these items from ford dealer only.

-Ben

 

[pdqb12]

i can help on the third bolt

My buddy and I changed the stat last weekend on my 91. It came off just fine. We struggled with that third screw , trying to put it back on for about an hour trying to use tape on a pen and the wrench with tape. Of course the socket doesn't fit in there. Finally after a lot of frustration and a couple of beers, I tilted the stat housing to the right and slid my hands in from both sides and started it with my hand. Ended up taking like two minutes, we just tried to make it hard on ourselves. Just make sure you do the 3rd screw first and be careful not to turn the stat itself when turning the housing.

 

[ToneDog]

Same thing on my '91 I changed everything

Water pump
Radiator & Cap
T-Stat
Hoses
Fan Clutch

Ect... Ect...

When I had the Head Gaskets Changed, the temp was solid as a rock!

Good Luck,
Tonedog

 

[gijoecam]

Balls! I was afraid of that... the head gasket would explain the coolant smell without a puddle... fudge... Anyone wanna buy a Ranger?

I'll be pressure testing it Friday... we'll see what happens.

-Joe-

 

[Ross-N-Chicago]

Just to make sure, you stated to "scratch that idea" concerning the vent hole--it should be on top. I too had the cycling temp gauge but also a lot of burping and clunking. I replaced the water pump (easy, 2 hrs or less) and now I am locked steady at the O of Normal. No fluctuation, FINALLY!