[COUGARCAL]

Hi,
getting a car running thats been sitting awhile- 68 289 2bbl ac, p/s if it matters with the big original radiator

after replacing the temperature sender in the intake manifold for a new one, the guage now works, but points to about almost 2 o-clock,. Wondering what your guages run when normal, is straight up 12 o-clock about normal?
(i put in a 185 thermostat with new gooseneck)
i thought the waterpump was rotted out, but just removed and it seems fine, never had a leak from the weephole, no shaft endplay etc.

wondering if maybe my radiator is semi clogged, i do see water moving a bit after the thermostat opens, but the level doesnt really drop when revving a bit.

or maybe theres sediment in the block i have to try and flush out next

thanks for any tips

 

[COUGARCAL]

Also i have one of those handheld trigger type temperature guages (i think centech makes it), where you aim and shoot to read surface temperatures,
is there a spot or certain spots on the engine where it should be a certain temperature, at its hottest,
thanks again

 

[Don Rush]

If you find cool spots in your rad fins that points too blockage... When you grab the upper rad hose is it too hot to hold onto? That is a oversimplified barometer of an engine that is running too hot. Does it have a shroud? What kind of fan? One trick to remove sediment is to run CLR in it for a couple of hours, this will knock all kinds of crud loose in your cooling system.

 

[Bad69cat]

190ish is about normal - the important thing is that it holds pressure and flows air. Wouldn't hurt to flush it out if in doubt......

 

[COUGARCAL]

Yes the upper hose is a bit painful to grab once the thermostat opens up,
it has the bigger(24 inch i think) ac radiator, lower outlet on passenger side, with clutch fan and original shroud
it definitley holds pressure, doesnt appear to be leaking, even overnight, you mean put clr in with the coolant and run motor don?

190ish is about normal - the important thing is that it holds pressure and flows air. Wouldn't hurt to flush it out if in doubt......

Is that190 degree with my surf temp guage, or if i had an actual water temp guage?
thanks

 

[Don Rush]

you mean put clr in with the coolant and run motor don?



Is that190 degree with my surf temp gauge, or if i had an actual water temp gauge?
thanks

I would carefully collect the coolant for reuse and just run water with the CLR, drain, flush and put your coolant back in. If a bunch of crap comes out with the CLR you know you have achieved some amount of good.

 

[COUGARCAL]

So where is everyones guage when running normally, 12 o clock, 1 o-clock 2 o-clock?

I'm having my radiator recored meanwhile
thanks

 

[johnboy]

Mine runs between 1/4 to 1/3 of the gauge. Never saw it reach half, and that includes a 4200 Km 4 day trip.

 

[Mercury6768]

I've had three standard '67/'68 Cougars and the gauge always showed about 1/4" above the cold notch unless the car was under extended load (i.e., going up a long hill, or the AC was activated on a really hot day while driving at low speeds).

 

[COUGARCAL]

I've had three standard '67/'68 Cougars and the gauge always showed about 1/4" above the cold notch unless the car was under extended load (i.e., going up a long hill, or the AC was activated on a really hot day while driving at low speeds).

great thanks! i was definitely running hotter than i should, ill see what happens when the recored radiator and water pump in,
thanks again

 

[wonderwrench]

You can't trust any temp gauge unless you prove its accurate. As COUGARCAL said get a non contact thermometer and check the temp at the water outlet/T stat housing. Most low cost non contact thermometers do not have adjustable Emissivity so for best accuracy the part to be tested should not be shinny. Chrome is the worst. Matte black is best though carefully applied masking tape works in a pinch. Normal operating temp on a non racing engine is between 200F and 240F. 200F being lightly loaded or no load and 240F being under heavy load and or extreme ambient temp. Race engines may be set up to run cooler to stop detonation or for other reasons but otherwise they also normally run 200-240F.

A well broken in engine will not be damaged unless the coolant temp exceeds 250F or more. Excessively high coolant temp will cause excessive oil temp which will cause non synthetic oil to break down. Computer controlled Ford's and GM's do not turn on their electric cooling fans until around 235F. Chrysler on the other hand seems to like 212F. Maybe Chrysler figures straight water and a bad cap on top of it? Anyone that claims an engine is running too hot if its uncomfortable to hold the upper hose has seen a lot of vehicles with stuck open or early opening thermostats.

Standard thermostats should start to open within +- 5F of there rated temp. They should be wide open 25F higher than rated temp. Trying to fix an overheat problem by replacing a 192/195F factory spec stat with a 160/180F stat will do nothing more than delay the overheat. If anyone has fixed a overheating condition by installing a cooler stat the one they removed was bad, end of story.

In my 30+ years as an auto tech most mystery overheats are caused by bad fan clutches/incorrect or no fan operation, plugged radiators, missing fan shrouds or low coolant level caused by a leak or bad rad cap. Thermostatic fan clutches will normally sound like a school bus on a cold start then quiet up after a minute or two if in usable condition. They will normally be locked up (aka school bus sound) at any temp over about 230F if not the clutch is bad. Signs of a bad fan clutch or an electric cooling fan problem, the vehicle only runs hot at idle or low road speeds. Signs of a plugged radiator bad stat or bad water pump impeller etc. the vehicle runs hot under most if not all conditions.

My two cents
Bill

 

[COUGARCAL]

Thanks for the info Bill, great stuff!
maybe i have fan issue as well... theres a pingy sound that you would swear is the fan hitting something (sounds like metal on metal- definitely not the shroud) but the fan seems clear of the radiator too?
is that the sound of a failing fan- all i can tell when it was running is that it spins all the time seemingly at engine rpm's
there is a little play when i grab it and do the wiggle test, seems like a little play between the clutch part and the shaft
thanks again