defiant1

Small block 350 with 185* thermostat and aluminum radiator. No problems whatsoever at cruising speed.

Today for example 100* outside, cruising down the highway at 70 mph and the temp gauge read 185*. Turned on the A/C and the temp gauge read 189*.

In town stop and go driving, the temp crept past 200*, then to 210*...230*... 245*

I do not have a shroud on this set up and it is the regular fan (non clutch). So, what can I install to help me with low speed driving?

d1

compedgemarine

you need to install a shroud. at cruising speed there is plenty of air forced thru the radiator. at idle the fan will pull air from the edges beside the radiator rather than thru it. early corvettes have a bunch of seals around the radiator and shroud to force the fan to pull thru the radiator. with one or two of the seals they start to overheat in traffic.

defiant1

My car is originally a non A/C car. Did they not come with shrouds from the factory?? I have a clutch fan off of a SBO 350 I picked up the other day. Would that help in conjunction with the shroud?

Redog

^^ I don't think so by itself but with the shourd, it would help.

I was looking at a electric fan on Summit. I'm not buying now, but the Summit brand of fans are on sale right now. If you go electric, you can pick the on off temp you want, but I would suggest getting the A/C relay. This way when the A/C is on the fan goes on too

CQR

Not sure a straight fan(without clutch) is correct for a/c. How harsh is the pitch of the fan? does it make a lot of noise at cruise speed?

msco123

I have a '69 Firebird convertible(in addition to my 2 cutlasses). It would run extremely hot during parades, which as you can imagine, involves driving around at about 10 mph. I changed the radiator but even this did not help. I finally put an electric fan(controlled with a switch under the dash) and have not had a problem since.

defiant1

I will check those out. Good idea on the relay.

Hell, I thought all fan blades were the same. I really don't notice fan noise at cruise speed. Of course, I wasn't trying to listen for it either. Hmmm.

I will have to compare the one on the car to the clutch fan and see if I note any difference.

CQR

When the fan on a clutch engages, you know it. It sounds like your in a wind tunnel at cruise.

jag1886

IMO you need to get the right fan shroud and put a thermal type fan clutch on with a new fan. I've been down the electric fan road before and found that they need to have a proper fitting shroud that covers the whole radiator to get good cooling and then you also have to make certain your charging system is top condition to keep up with them. Check the amperage draw on those electric fans, some are huge.

defiant1

OK, but since I do not have any mounting tabs to fit a shroud from a circa 1970 Cutlass, what other options are there?? I believe I would have to buy a new top plate and purchase and affix mounting tabs at the base of the radiator.
If I got to spend a little to ensure the cooling system works, I'll do it, but I only want to have to do it once and not try multiple things.

Friend of mine has a "gorilla" motor in his 52 Chevy Coupe. He only uses 2 electric fans and it stays at 180* at idle or in parade mode (he uses a 160* thermostat). Seems to be a divide between the "electric fan" group and the "mechanical fan" group.

cutlassjoe

I'm also running a 350 slightly built. It originally had the 4 blade non a/c fan with no shroud when I bought it. I went to a 3 core rad, 7 blade clutch fan, and the shroud. I was at a car show and it took about 45 minutes to get the cars parked (the show was in a downtown core, we parked on the street) It did not go above 190 with the 185 thermostat. I know running a/c puts more strain on the car, but you should be running the proper radiatior, fan, and shroud. Just my .02

Lady72nRob71

Yes, the non-AC and AC cooling systems are different. As we know the shroud and high capacity clutch fan came on the AC models. Also the water pumps are different.

That 4 blade fan i would consider barely adequate. Do find a better one. Either a clutch and AC car fan (if it will fit your water pump) or a flexer.
My old Ford had a 4 blade heavy steel one and I changed it to flexer. Even with no shroud, it improved its cooling.

Electric would be my last choice. You would most likely have to upgrade the alternator to provide the extra 20 amps or so needed at idle. Also more wiring.

defiant1

Where did you get your shroud (off a another Olds or custom made) and how did you mount it?

Tony72Cutlass'S'

Hey,

I was thinking of buying a shroud for my car too, the last time it ran it was creeping up towards 210* at idle...

I was looking at Fucisk, they seem to have a nice shroud for around a hundred dollars? Maybe check that one out and others will chime in if they've bought them or not.

Cheers,

Tony

jag1886

I think maybe you need to be looking for a junk Cutlass of about the right year that has everything on it you need and I'd be looking for a car that had air so it has the big radiator. I know it's a pain to do this but you can't beat the money Oldsmobile spent developing a proper cooling system.

defiant1

I am picking up what you are putting down. Unfortunately, in my neck of the woods the "Cutlass" is an endangered species. Which is good and bad. Good: get lots of compliments and admiration for my car. Bad: Can't find parts locally to save my life. If it wasn't for this forum I would not have half the parts I needed.

But you do bring up a good point and refreshed my memory. There is a 4 door Cutlass around the 1970 yr mark that is sitting dormant in a town 40 miles away. I may need to make a road trip... The wife is going to hate me if I bring home an orphan car...

71 Cutlass

Call Ron Memmer in Indiana. He's fairly close and will have good used parts...everything you need.

defiant1

I picked up a radiator top plate from a member of this site. The top plate is designed for a shroud. The one I have currently is not. I compared the two and they are the same width (from side to side) and the saddles match each other. But the depth (from front of car to back of car) is different. The one I just got is about 2" away from the mounting holes on the core support.

Now looking at the radiator, the top leans towards the motor a little. Will standing the radiator up close the gap or do I have the wrong top plate?

d1

defiant1

Figured I'd better post pictures (Eric has to have his car ****) so one can visualize it better.

cutlassefi

Other than that, how's it run Shaun? Get everything else sorted out?

defiant1

Mark

Still fighting the Q-jet at idle. I am all over the map with the timing, throttle blade opening, idle mixture, vacuum and even when I thought I had it at a happy medium the motor started "dieseling".

I am trying an Edelbrock 600 this weekend and hopefully it goes better than the last 2 months of fighting with the Q-jet.

But when I get it out on the open road it runs well. I installed the 3.23 posi rear end (compliments of monzaz) and I am chirping the tires "going through the gears" as it were. Good combo so far. Just need to get the carb figured out so I can move on to other projects on the car.

Shaun