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Was: 160 degree thermostat for a 1968 Now: cooling off a 1968 DeVille

Started by cadillacmike68, August 12, 2014, 11:45:03 PM

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cadillacmike68

Anyone know where I can get a 160 degree thermostat for a 1968 DeVille? The norm was 180. It's too hot down here and the car needs some help in backed up traffic. 
Regards,
"Cadillac" Mike

SixDucks

Hi Mike,
You should be able to find a 160 degree thermostat at any auto parts store. I recommend a thermostat that is manufactured from stainless steel if at all possible. I believe Stant has these available. The stainless thermostats resist corrosion and are less prone to malfunction caused from electrolysis.

Terry
Current:
1941 coupe
1962 Fleetwood
1988 Brougham
Previous:
1956 Series 62 Sedan
1963 Fleetwood
1975 Fleetwood Brougham D'Elegance
1989 Brougham

cadillacmike68

Yes, but will it fit in my 1968?

I just remembered, I have a NOS 180 deg one. I'll take that along to confirm the size.
Regards,
"Cadillac" Mike

SixDucks

 I believe Stant calls them  "Super Stant". I have one in most of my vehicles.

Terry
Current:
1941 coupe
1962 Fleetwood
1988 Brougham
Previous:
1956 Series 62 Sedan
1963 Fleetwood
1975 Fleetwood Brougham D'Elegance
1989 Brougham

dadscad

I agree with Terry about the Stant Thermostat. I had running too warm issues with my 63 for years using the parts house brands of thermostats. I put a top of their line  Stant Premium thermostat in the car, problem solved. The car now consistently runs between 180 -190° where before it might get up to 230°.

A thermostat has about a 23° operating range from closed to fully open. If you have a 180° thermostat installed, it will be fully open around 203°, giving maximum flow. Is your car running at a temperature over 203°? If it is, a 160° thermostat will be fully open around 183° and will not necessarily cure the over heating situation but may slow the eventual rise to over heat condition. Is the radiator and cooling system in good clean condition? Fan clutch good and the radiator not plugged with bugs, etc?

Enjoy The Ride,
David Thomas CLC #14765
1963 Coupe deVille

Gene Beaird

It looks like a thermostat for a mid-70's Chevy Truck has similar dimensions, so you may be able to find a 160-deg unit on the shelf for one of those.  I agree with David, though, make sure the rest of the cooling system works well.  I think our 68 Calais has the standard thermostat in it, and the car has never spent any appreciable amount of time north of the Mason-Dixon line.  Much of it's life has actually been in the Houston, Texas area, and we've never had an overheating issue with it. 

Gene Beaird,
1968 Calais
1979 Seville
Pearland, Texas
CLC Member No. 29873

TJ Hopland

The proper stat for the 472-500-425-368 has that extra disc at the bottom to close off the bypass passage when its fully open.   Without that passage blocked there will always be a percentage of coolant flow that does not go through the radiator so in theory the total cooling capacity is slightly reduced.

John Deere apparently used the same stat on some of their equipment and supposedly still make a quality unit.  I don't have the part numbers handy but I bet someone will. 

There were also the 'balanced' stats that had the fairly large cup valve instead of the typical flat disc one.   They were supposed to flow better too but apparently have not been made for the Cadillac / Deere app with that bottom disc for a long time.   It may have been Robert Shaw that made those.  They still make em for some apps like the common Chev and Ford ones.  There was one in my 73 when I got it but it was stuck open.  I tried to find another one but came up short. 

You have to be careful going cooler especially on an engine that does not get regular driving.   Lower temps tend to let a lot more 'crud' build up in the engine.   Infrequent and short trips just make it that much worse.    Like someone else said a lower stat is not going to help at all for running hot or overheating issues.  Once its open its open no matter what the temp is and if the cooling system can't handle it it can't handle it. 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

cadillacmike68

#7
The rest of the system is fine. The condenser is new, and it has protected the radiator from bugs, damage, etc. I had the original tanks re-cored to a 4 core in 2005 when I had the entire engine overhauled (and bored to .030 over). The radiator was rodded and cleaned in summer 2012 before I deployed the last time.  Coolant was changed then and tests good. Fan clutch is new and working properly. Belts are new.

It works fine while driving, the gauge usually sits at the 1/4 mark. But this heat and the climate control put an extra load on it when stopped, and the traffic here can get very bad very quick. The gauge will then creep up - sometimes way up. Once I get moving it cools back down.

Some folks tell me that the boring out will cause it to heat up quicker than before, especially  when stuck in traffic, don't know if that's true or not, or to what extent.

Thanks TJ, I probably need to pull the stat that is in the car and check it or just replace it.

The car gets regular use and warms up before I get out or my development.  so I'm not concerned there.
Regards,
"Cadillac" Mike

TJ Hopland

Here is the one with the disc at the bottom.    Doing a quick look all I can find that have that is 180 and 195's.



Picture from www.500cid.com who does sell them (and other cool stuff) if you can't find the correct one anywhere else.
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

TJ Hopland

Another thing that may be worth doing is getting one of those IR temp guns and do some probing to see what the actual temps are.   If it will heat up just sitting you can take readings and 'calibrate' the gauge so you know what the actual temps are at various readings.   Factory gauges were never known to be that accurate or linear.   I have had cars where if 200 was 1/4  3/4 was only like 220 which is still well within the operating range of a pressurized system.  If everything is working as it should you should be able to get over 250 without boiling.

Historically I have not had cars with working AC so I usually removed the condensers.   The last few years the AC has become more important to me so I have been fixing them.   What I have found is that with the condenser there more crap seems to be getting stuck in the radiator than when I didn't have anything in front of em.   I don't know why, maybe it being there lowers the air pressure so stuff does not just blow out?    My Suburban was running hot this summer and I had had everything apart and clean when I got the AC working a couple years ago so I was not thinking it had a dirt issue, its not a daily driver.  I was thinking of replacing the fan clutch while I had the air hose in my hand and for some reason decided to shoot some air at the fan.  I was a amazed at the poof of dirt and stuff I saw come out the front so I took the upper shroud off and got the garden hose and long extension on the air hose.   Running warm problem was solved.

A tip for cleaning that stuff is go buy a product called 'Bugs B Gone' and spray it in the front of the radiator and condenser, let it soak for a while, then hose it off.    It breaks down organic stuff (like dead bugs) so they are more easily removed.  Does not seem to hurt paint either, I have used it to clean dead bugs off the front of the hood and bumpers.    Also works well on bird crap and grass stains if someone cuts wet grass near your car.    Recently tried it on 'pet stains' and it seems to help there too, guessing due to the whole break down organic thing.
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

35-709

AFAIK there is no GM or aftermarket thermostat available for the 472/500/425/368 engine other than a 180 or 195.  A Chevrolet thermostat will fit but will not function correctly.  TJ posted a picture of the correct one below and any good parts store should have them.  These cars cooled fine when new and if the cooling system is properly maintained and in good condition should do fine today.  Putting a low temp thermostat in is only an attempt to band-aid a problem elsewhere.  As TJ Hopland pointed out ---

"Like someone else said a lower stat is not going to help at all for running hot or overheating issues.  Once its open its open no matter what the temp is and if the cooling system can't handle it it can't handle it." 

I would change the thermostat (making sure it is the CORRECT thermostat for your 472) as it might be faulty and not opening fully, after that you can try an electric fan in front.  But still, there is a reason for the overheating.
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible - Sold
1950 Packard 2dr. Club Sedan
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2

cadillacmike68

I have one of those Fluke IR temp guns, just need to find which box it is in. I packed up and sent home some 20 boxes while I was away and its' in one of them.

Rad is clean, I hose it off regularly. I'll check my NOS stat against that picture.

I've always had the climate control working, and that does put an additional strain on the system, especially here.

On the gauge, I completely understand. I'll definitely need to "calibrate" mine so I know what is what. If it's as you mentioned, then I have nothing to be concerned about.
Regards,
"Cadillac" Mike

Scot Minesinger

I don't think a 160'F stat is really going help the car run cooler.  Once it reaches 160'F or above any benefit is gone and the result would be the same as a 180'F stat which is what I run my 1970 Cadillac.  Since the 1970 did not include a temp. gauge I installed a real good Autometer one and always know the temp.  The temp typically runs between never hotter than 210'F in normal driving at 95'F and sunny.  However, if in a traffic jam with a/c on and it sits idling for an hour it is going to keep up to 215, maybe 218'F or so.  220'F is the point where the factory idle speed up engaged to spin the fan faster and provide more cooling.  I have driven it in 102'F weather no problem.

The car was designed to operate in hot weather with a/c on so you should be good.  On my car I did change to a 4r radiator when original went bad and those dessert air radiators are also available for a 1968, but you have to be careful that the fan clears the thicker radiator.  To add insult to injury the replacement fan clutches are deeper, pushing the fan closer to the radiator.  Also, I changed my fan to the 7 blade commercial chassis type instead of the five blade.  This does move more air but noticed it seemed to have a little effect on performance.

For your car be sure the fan blades are in proper planer alignment with fan shroud (clutch could be deeper), you may be able to use a shallower spacer.  Be sure there is no place for air to go around radiator between sides/bottom/top of radiator and shroud housing.  Be sure the rubber sheet at bottom is in place.  Make sure timing is correct, even too advanced is no good, retarded is bad.  If the water pump is old, it should be replaced.  Consider a commercial chassis fan as it does move more air.  Make sure fan clutch is good.  Make sure idle is high enough and the idle speed up with climate control works too.

Usually I drive top down w/ac off unless it is below 50'F or raining.  If you see my car driving top up on a hot sunny day, it has been stolen.
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

Jon S

I read all of the posts and hesitated answering, but Scot hit the nail on the head - the purpose of the thermostat is to bring the  operating temperature up to a certain level - be it 160, 180, 195, etc.  Once that temperature is exceeded, the thermostat remains open and the cooling components take over - radiator, water pump, ambient air temperature.  So, other than for winter driving when a 180 degree thermostat provides better heater heat than a 160, in summer driving replacing a 180 with a 160 really has no effect; especially if you are running 200+ degrees.
Jon

1958 Cadillac Sedan De Ville
1973 Lincoln Continental Coupe
1981 Corvette
2004 Mustang GT

cadillacmike68

#14
My two NOS 180 stats look like the one TJ pictured, however one of them has a cracked cup that where the bottom disc clamps onto the main unit, so it's most likely no good.

as I have stated, the rest of the cooling system is fine. It only acts up in very hot weather (all the time here in FL) and when stuck in traffic (which was NEVER like this in then 60s)

You guys anywhere else don't know how hot the road surface can get here in FL on a sunny day. It can easily get over 130-140 degrees with air temps over 115-125 in stopped traffic. That's HOT. And all that Hot air is being pulled past the condenser first, then the radiator with more heat radiating up from the asphalt. Even in AZ & NM where it gets just as hot, that's Dry air, not this 95% humidity that we have in FL so that nothing cools unless a hurricane is blowing over it.

Took the car for a 30 mile drive this evening, gauge never went over 1/4. Outside Temp was around 91, but no sun load on the road, and no stuck traffic. It was a Nice drive.

I'm going to try and get that broken 180 replaced by the vendor and will check out my other one. I'll also try to "calibrate" the gauge so I know what the marks really mean.

I checked out MTS (500cid.com) and their stat price is reasonable, so I'll get one. They also show a new water pump that has a closed turbine style impeller. It looks just like the new ACDelco pump that I bought as a spare.  It's supposed to have 25-30% more flow at idle, so that might be a good thing to install with a new stat. It can't hurt.
Regards,
"Cadillac" Mike

35-709

I am a year-round resident of Florida, and live just south of Melbourne on the east coast.  My '73 472 runs cooler in summertime stop and go traffic, with the AC on, than it does at 75 MPH on I-95. 

The water pump that MTS sells is a "Flow-Kooler", you might find Flow-Kooler's website interesting ---
http://www.flowkoolerwaterpumps.com/

I have a Flow-Kooler on both of my Cadillacs, the '73, and my 1935 472 powered Cadillac  resto-mod sedan.  I put them on both cars during their restoration because they both needed new pumps and I wanted to have what I thought would be the best.  But I STILL say the stock pump and cooling system should do the job in Florida, or Arizona, or south Texas, etc.
   
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible - Sold
1950 Packard 2dr. Club Sedan
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2

cadillacmike68

Thanks for the link G. I'm checking it out.

Stop and go traffic is OK. Its the stop and stop here in Tampa that is not OK. You guys have a near constant sea breeze there. I'm some 30 miles in, and that's a big difference.
Regards,
"Cadillac" Mike

cadillacmike68

Looks like Flow Kooler sells the Robert Shaw stats, so I'll  get one of those instead. I'll also check timing and the fan shroud &all the other air flow items.

As a note to two posts up, running at higher speeds does cause it to run hotter, the temp gauge goes part way to 1/2 above a steady 75MPS speed.

Yesterday, I ran it right up there to the 9th speedo quadrant, and sure enough it went to the 3/8 - 1/2 range. And even when I slowed down, with all the long traffic stops it stayed there until we got to the restaurant. But when we got out and went to a cafe, and later the long return trip, it stayed right at 1/4 all the way, even when stopped  at 2 minute lights.

The hot daytime temps here are definitely driving me crazy.
Regards,
"Cadillac" Mike

Scot Minesinger

Mike,

I have the stock water pump, but the seven blade commercial chassis fan and the 4 row radiator.  Got stuck in traffic on way back from Boston GN for 3 hours traveling about 5 miles in 95'F temps with strong sun in the afternoon.  Top was down and the car stayed around 210'F or so.  Probably would have been 215'F with a/c on.  Car does not like 230'F, so if I stay away from that I'm good. 

I think it was pre-Christy "Bridge gate" and he did not get caught that time, because it seemed like traffic was stopped for no reason.

Please post on if that water pump is an improvement, would really like to know.

You should get a real good temp gauge that tells the real story and see what temps you are running.  If 3/4 of the way corresponds to say 210'F then you should have no worries.  Weird how the temp goes up so much at speed.  At 80mph, mine never goes above 205'F during real hot weather - but my fan is also still working albeit at reduced capacity (no clutch - flattened blades).  I bet you are Ok and gauge is leading you wrong a bit.

BTW if you ever get in trouble you can trick the climate control into full heat and it lowers temp about 10'F.
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

chrisntam

I got the flow kooler pump, 4 core (new) radiator, water wetter, "supposedly" cleaned out block and mine seems to run warm.  Though I don't know what the water temp is though.  I expected better from my set up, especially the flow kooler pump (advertises better flow at idle) and the water wetter (advertises 20 degrees less water temp).  I'm still working on mine, though I haven't had time to actually "work" on it and start doing things.  Work, yard work, house work and normal life are getting in the way.   Soon, vacation will get in the way.  Then starting a new job (same job, but new location-farther away).  It's always something!
1970 Deville Convertible 
Dallas, Texas