whats the easy way to change T stat

[flmont]

Well...I need to change the engine mounted T stat in the 81'...Do I have to drop axel's and oil lines,..or can I lower it enough to change it out easy ???? Thanks FM

[sammyg2]

Hmm, I'd say you have to remove the CIS to get to the thermostat,
I gotta go with pull the entire engine. Much easier that way.

[john walker's workshop]

engine out.

[flmont]

Do I need to drop the axels and remove the oil lines..??? FM

[Jim Sims]

Oil lines have to be disconnected to drop engine. Axles may be left in place if dropping only engine. Some prefer to drop the engine and transmission together. In this case the axles plus shift linkage conection must be undone at the transmission. There are other items that must be disconnected when dropping the engine or engine and transmission. Buy some books and do some searches on the topic on this board. Cheers, Jim

[flmont]

Jim,..I had done a top end rebuild on the engine...but it runs hot so I figure its the T stat...I'am somewhat familiar with the engine R&R...I was hoping to lower it just enough to get to the stat...The P mech said they just lower it a few inches to get to it,But I'am not sure if the Eng Tranny combo will strain the axels,.Or could I get it low enough with them attached to do the job,I have enough travel in the oil lines if I only need to drop it 5-8 Inches..but can the axels flex the correct direction for it to lower easy ??? Thanks Frank

[Jim Sims]

One can do a partial drop without disconnecting the axles to gain access (this is done all the time) but I don't know if you can go down 8 inches. The thermostat job may still be a "pain" (even with the partial drop) depending upon what parts of the CIS system are in the way. Also, one has to be aware of what the front of the transmission is doing; the shift coupler will have to be disconnected if you lower too far. Some of the wiring on the driver's side of the engine may run out of slack and also the high pressure hose from the A/C compressor (if installed) if you lower too far. As an aside, I'd check the other possibilities for the causes of running hot (starting with a bad sending unit/wiring, mixture, air leaks, etc.) before going to the trouble of replacing the engine mounted thermostat. Cheers, Jim

[Chuck Moreland]

You can do a partial drop on a CIS car and reach the tstat. But it's not easy, very limited space to work with. It might just be easier to pull the engine and be done with it.

[RoninLB]

Originally posted by flmont


...but it runs hot so I figure its the T stat...

so this means you already have a front fender oil cooler, your ignition is ok, and your temp sender and gauge are ok +.

[flmont]

Yes,All possibility's have been ck'd,shop also ck'd with a Pyrometer,New sensor's Etc.. I installed a front cooler and it did not drop the temp at all, plus it heats up so quick,So it seems its not even getting to the engine cooler aswell....Thanks for all the Info guys....Frank

[flmont]

Well,...The T stat open's seemingly just fine at near 200 Deg's now what ????,...........FM

[Jim Sims]

Depending upon what a top end job entailed in your case I'd check: cylinders (not upside down) and air baffling installed correctly; somthing like a rag left on top of engine; cork or rag left in oil line partially blocking it. How's the oil pressure? Jim

[john walker's workshop]

remove the mouse nest material from over the cooling fins and top of oil cooler? oil and dirt can block airflow to the cooler. pull off the gray fiberglass cover and take a look. you may have the largest crank pulley already, but if you can go larger, the fan spins faster. the 78/79 SCs had the largest one.

[flmont]

None of the above,..I did the top end..then I had the shop do the cam timming and they ck'd all that for me,..I just put up a pic of the T stat in open position on the engine rebuild forum Iam sure its open enough Ollies cleaned and tested the cooler I dont think its blocked went from bag to engine in 5 Min.....Shold I blow air thru it from the engine side ????..FM

[flmont]

Oh ,..Oil pressure is fine.. warm its 25lbs..or so at Idel ,..cold about 80lbs Hot reads about 5 ....FM

[john walker's workshop]

you haven't said how hot it gets and what the ambient temps are at the time.

[flmont]

Sorry John...Well yes Tucson az...95-105 deg days with some humidity,..but even at night when its cooler, it will still get that hot ??FM