DJS70cutlass

Ok so I'm trying to install a fan shroud in my '70 S and I'm running into a couple issues. The car did not have a shroud at all originally and as a result it get's up around 210-225 in very short order if you have to sit in traffic. It's been like this for 15 years and this is the year it's gettin fixed haha!! I have a 402995 shroud and AC top plate.......and upon test installing the fan is WAYY too far forward in the shroud. At first I thought a shorter fan spacer would fix it.........but the fan is already less than an inch from the ps pump.........and it's gotta go back AT LEAST that far....if not more I know that factory AC cars used a clutch fan.......would one of these fit the shroud as intended without spacers? Is it smaller in diameter? I'm open for any suggestions at all at this point guys. Here's a couple pics that may help Also what on earth is supposed to hold the shroud at the bottom?

IMG_1950_zpsd8ffe045.jpg

IMG_1951_zpsd1263889.jpg

Allan R

AC and those with HD cooling had different pulleys and water pump.
The stock fan for those cars was the 6 blade with fan clutch, and the fans were 19" which fits the inside of the shroud quite easily.

The bottom of the shroud needs 2 metal supports that get tack welded to the frame. I have a diagram of how it fits on my other computer I can post for you later?

IMO, if you have that serious a problem with temps, your timing is most likely out of whack.

Octania

The assembly manual should have illustrations of how the shroud mounts as well as the configuration of WP, fan, fan clutch, pulleys, etc. used.

Is your Thermal Vacuum Switch hooked up?
It's supposed to send full vacuum to the distributor if overheating is imminent. It's a tall slim 3-hose item mounted in the water passage at the front of the intake. Nipples marked C, D, MT for Carb, Distributor, Manifold Tap. All this is explained in the Chassis Service Manual which you should also have or have access to thru the FREE site/ experience WildAboutCars.com. Seek and ye shall find.

and, yes, your timing should be as far advanced as you can get it w/o detonation. If you have to retard the timing, one easy solution is to buy higher octane fuel instead.

DJS70cutlass

Does the clutch fan sit farther back than the fixed fan/big spacer setup I have now? Are the 4 and 6 blade fans the same diameter? I guess the real issue I'm having is for the fan to sit where it's supposed to it needs to fit on the same plane as the ps pulley nut......which obviously cant happen with my existing fan As far as the timing, this issue has been occurring through several different distributors and timing settings with no change. A long as you don't have to sit stopped the motor runs great....and doesn't get above 185 ish.

DJS70cutlass

What's that? And I don't know if it's hooked up

Allan R

The 4 and 6 blade fans are both 19" IIRC. The shroud gets shims at the top as required to make sure the fan is properly centered. Let's see a pic if your rad top plate. You may need to change it for installation of the shroud.

Does your car still have it's TVS? If yes, check to see that it's hooked up right. I'd do that before trying different octane fuel.

Allan R

Ok, I'm on my other puter. Here's the diagram that shows how the fan shroud installs.



The tabs at the bottom can be purchased at aftermarket vendors. I bought mine from In Line Tube, but there are others as well.

Motor City Supercars - ILT

lunaboy

easy things first ... if you do not have the proper clutch fan get a proper one /shorter spacer... if no help, chk that the radiator is circulating
90 % of cooling issues is a clogged rad. also there is an 18 in clutch fan if back-spacing is an issue or even the six banger 17.5 reg fan. the 71 72 fan shrouds are larger if your existing fan is 19.5 + also dif water pump lengths ect...

DJS70cutlass

Ok here's the pics Allan, and as far as the TVS I have no idea......so I'm leaning towards it NOT having it haha!

IMG_1952_zps61c735a6.jpg
IMG_1953_zpsd6f178ab.jpg

DJS70cutlass

Oh I guess should've mentioned that........but the radiator is brand new. Replaced for a different issue

DJS70cutlass

Ok with that description my car definitely doesn't have that

Allan R

Well I see you've installed a 4 row radiator. It's the right top plate for that and the oval openings on the plate are the ones you need for the shroud.

DJS70cutlass

That's not why the fan hits the shroud is it? Would a factory clutch fan setup be farther back........but not too far as to hit the ps pump shaft?

mrolds69

A few observations and comments...If your car originally came with a 4 blade fan, AND it's the right fan + spacer with a new rad it should be cooling fine. You need to blow the hot air out, I see your splash shields are worn or missing. I also notice you are missing the side flaps on your top plate, and I can't tell if the baffle below the core support is there. All of these things hurt cooling a bit. If you are going to use a shroud, you should get a clutch multi blade fan. Like I think Allen said, there could or will be pulley issues also. Is there a thermostat in the car now? What's the temp of it? If there is no stat, then the coolant won't stay in the rad long enough to cool. Water Wetter is good for maybe 10 degrees. All things to think about.

DJS70cutlass

Yes the fan/spacer are the correct for non-ac.....they have the correct #'s right in the parts. I know about the side flaps......the non-ac originals wouldn't fit the new plate.....I'm getting those really soon. As far as the splash shields.....do you mean the ones on the inner fenders? If you do then yes they are long gone. The baffle below the core support is there. I was gonna use the shroud cause the only time it ever gets hot is if you get stuck in traffic in hot weather.....parades would be a no go. I did notice that at normal temps there was barely a trickle through the radiator core at idle.....but picks right up with an increase in rpm. There is a t-stat in it......160 degrees as I recall. I'm extremely sure all the pulleys on the car are original to it......knowing it's history. I'm really leaning towards a clutch fan.......just because it's what the factory would have used correct?

mrolds69

Ok...right..the inner fender splash shields. No shields can actually hurt cooling in the engine compartment...moving, stopped or slow I'm not sure. No...the fan on your car would have been a 4 blade no shroud fan. 160 temp thermostat might actually be hurting your cooling. I would go back up to at least 180. I've actually heard more is better. When the cap is off and the car is at operating temp, you should see the coolant moving. Check for a spring in the lower rad hose by squeezing it. It might be collapsing if it's gone. Check the cap to be sure it's the right pressure...15? Finally, the water pump looks like it maybe was changed. Maybe an AC pump on a non-AC car? You kind of have to check everything to see what's happening. Does your heater work really well?

Allan R

Well, the rad is new and it's a 4 core so it should be flowing well unless the water pump isn't doing its job. The one I see in your pic is designed for a 2 row radiator so I'm thinking that's part of your problem. If you do change the water pump, you will need a new pulley guaranteed. Can't remember the code off the top of my head but I think something like KK?

I'm inclined to think that since your car doesn't have a TVS, your timing is too far retarded at idle and that's causing your problem. Try advancing your timing overall until it hurts your performance. Either that or buy a TVS and install it. They're reproduced and not hard to find.

As mentioned by mrolds69, get the required cooling masticated rubber parts installed. That makes a world of difference channelling the air. If you need a reference, look up the cooling section in the 70 Cutlass Assembly Manual. It will also guide you on the correct pulleys needed for the changes you have planned.

re: T stat? There should be a marking on the T stat that says "front". If you installed the T stat backwards (not upside down) it can also impede the flow of coolant through it.

DJS70cutlass

Ok I'll add those to the list then haha! Yeah that's what I have now......and is in my pics. Really?.....I hadn't heard that before about t-stat temperature. The lower hose has a spring in it and the cap is 16 psi. And yes I replaced the water pump probably 10 years ago.......I'm sure it's the right one. I have an ac pump and it's longer than the one on the car. And yes my heat works great......it'll drive you out of the car

DJS70cutlass

Wait there's different water pumps for different radiators? How can you tell my pump is for a 2 row? Where would I find the 4 row pump and pulley if you don't mind me asking? I'm gonna look at my old intake and see of the TVS is in it........although a new one might be a better choice at this point I think. And about the thermostat.......I have no clue if it says front on it, so I'll be adding that too the list too.

Allan R

There are different pumps for different applications. Usually the AC cars had a higher capacity water pump and/or HD cooling. Note the profile of the water pump and lengths in this thread at Oldsmobility.com

Yes, I can tell just by looking at your water pump pulley that it's a lower flow for a 2 core. That's also one of the reasons your car has a spacer to extend the 4 blade fan closer to the rad and pull more air through there. An HD pump will have a longer snout compared to the one you have on there. The pulley for the HD pump is a bell flared unit that sweeps back over the WP snout and is designed to work with a fan clutch. Depending on the depth of the bell (hence the codes of the pulley) it will affect how your belts line up.

Check the Cutlass Assembly Manual for the pump pulley code you need. There are 3 different length HD water pumps. Have a look at this thread. It will help you understand what you're getting into.

MDchanic

Sorry, guys, but AAAARRRRRRRRGGHH, No!


No. Cooling has nothing to do with the amount of time that the water spends in the radiator. This has been thoroughly debunked on this board.
The reason why you will get better cooling with a thermostat than without one is that the restriction provided by the thermostat produces a high pressure condition inside the block (up to about 40psi), which provides for better contact between the coolant and the block and heads, reducing points of micro vaporization, and picking up heat more effectively.



No. That doesn't even make sense. It is true that in an engine with an inadequate cooling system, using a lower-temperature thermostat won't help (because that's not the problem in the first place), but it will not hurt your cooling either.



Could you explain that? Where have you heard it? Why is it better? In what way is it better?



No. Collapse of the lower hose because of pump suction occurs at high engine speeds, and usually causes overheating on the highway.
His problem is overheating at idle, when the water pump NEVER collapses the lower hose.



No. Whichever pump you use, it will not reduce the cooling on a non-A/C car.
An A/C pump will have a different length shaft, though, so if that were the problem, he'd be talking about his pulleys not lining up.



No. Why would a pump that was adequate for his engine's cooling when it was built suddenly become inadequate when he changed the radiator?



No. TVS will advance the timing when hot, by switching to manifold vacuum from ported vacuum, at something like 220°F. If his cooling system is adequate, his engine should almost never get that hot anyway, so it should never even have a chance to kick in.
You may argue that IF he is running ported vacuum, the TVS would help, but you don't know whether he is running ported or manifold vacuum, so this is really a red herring.



No. Factory thermostats had that marking, but as far as I know there are no aftermarket thermostats designed with the factory directed-flow feature.
He will spend a lot of time looking for a stamped word that was never there.


This thread is beginning to turn into a "worst of the internet" hail of irrelevant or misleading information.
Give the guy a break, and think about this stuff before pressing the Post button. He's having a hard enough time already.

His problem seems almost definitely to involve inadequate air flow at low engine and car speeds, and therefore his idea of adding a shroud and a larger clutch fan is a good one.
In order to do so, he will have to transfer the entire water pump, pulley, and belt system from an A/C or heavy-duty cooling car, because, as he has discovered, just adding one part will cause alignment problems.

In all likelihood, the root of this problem is in his decision to go with a four-core radiator when he replaced his 2-core: The four-core is at least twice as thick, which means that the air must travel much farther through narrow rows of tiny fins, encountering much more resistance. The thinner radiator was easier to pull air through, so all GM needed was a cheap stationary fan with no shroud to do the job, but the thicker radiators required much more "suction" to pull enough air through them, so GM had to design a more effective fan system, and then had to design a clutch for it to quiet it down at those times when it wasn't needed.

- Eric

Allan R

So you're saying the amount of coolant flow doesn't matter? I'm going to have to check and see how much flow difference there is between HD and non pumps. I do agree with your statement however about air flow. In order to get that however, he has no choice except changing to an HD water pump.

Maybe, but the inference was about his car running hot. My comment may be awkward in the approach, but I think it's related and relevant.

Gee, I think we were on that path already.

I hate to argue with you, but I have aftermarket gates T stat that says "front' on it. Pulled it out of my 72 6 years ago and I know for a fact it's not original. Want a picture?

2blu442

I've got a 1970 442 that I used as a daily driver through the 1990's. When I moved to Medford where there's a lot of high 90's and some low 100's in the summer I found it would overheat at traffic lights when I was downtown. I replaced the 3 row with a 4 row radiator and added a shroud. I already had a 6 blade clutch fan on the engine. The larger radiator and shroud fixed my problem. I think the others are on the right track saying you need to change whatever is needed in the way of pulleys to install a clutch fan and still have your belts line up. Then install the shroud you've already purchased.

My 2 cents.....

John

DJS70cutlass

Yes Eric that's exactly my problem.......insufficient airflow at slow vehicle speeds. So in order to run the shroud I'll need an AC water pump, pulley and belts? I have an assembly manual and it looks like I need a "KF" pulley pn 399404. That pulley seems to be a three groove one......so is this the pulley I need?

http://www.opgi.com/cutlass/1970/coo...pumps/C241418/

Also previous to the new four row radiator I had been running BeCool aluminum rad....for more than a decade........but it started leaking so it had to go. The overheating when stopped issue was more or less the same with the BeCool and the stock two row. Where would you recommend I get the fan clutch and fan if you don't mind me asking?

2blu442

I'd go with a used pulley and save yourself $50, find a used fan then purchase a new clutch for it. I think you could get a good clutch at your local auto parts store or online at RockAuto.com

Several members here have extra used parts. I've got the pulley but am not sure I have an extra fan. I know Scott (oldspackrat) in much closer to you than I am. You might see if he has both to save on shipping.

John

mrolds69

Hey, I was just tossing out ideas, nothing that would cost any $ to do, but worth checking IMHO. It's true what Eric says, and that makes sense to me now, that the thicker rad might actually be a contributing factor. I was just trying to help, and I'm not too excited about being mentioned as a candidate for the "Hall of Morons". So...I guess these guys with far more knowledge than I can help you out. Different people have different ideas. Personally...I wouldn't do anything w/o checking the stat 1st for worthiness and temp, but...hey...that's the way I do stuff. Sorry to give bad advice, good luck with the prob. Let us know what works.

MDchanic

Not exactly. I'm saying that too much coolant flow doesn't matter.
Too little would be bad.



Please do. I would be very interested in knowing any flow specifics on any of these pumps.



I agree - because of the shaft length and need for proper pulley alignment.



I just don't want to send him chasing after a TVS unit when he may already have the distributor on ported vacuum.
While it is not false to say that the TVS changes the timing, I think it is important to describe how it does, so that he (and others) can use that information to properly analyse their cooling problems.



Of course we were.



That's not arguing, that's providing useful information.
Yes, I'd be very interested in seeing a photo.
Even the Mr. Gasket-branded Robertshaw (from NAPA) that I installed today had no such markings.



Actually, I believe that you need a fan, clutch, shroud, water pump, water pump pulley, crank pulley, and possibly a ower steering pump pulley, and the brackets to relocate your alternator to the other side (not sure about that one)... and belts.



I am interested in whether it overheated in traffic with the original two-core (at least before it spring a leak, got blocked up, or whatever...).



I'd get all of that stuff from John (above) or Scott, if they've got it, or, perhaps better (because you can see where everything goes), at a local junkyard, if you can find one with an old Olds in it.

- Eric

MDchanic

Nobody nominated you for the Hall of Morons (or the "Wall of Shame" thread).

There was just a sudden blizzard of information and suggestions, many of which clearly didn't apply to the questions at hand, and I thought the OP (and any future readers) could be easily confused.

Also, to use Joe's term, I believe it is very important in internet postings, which may (or may not) be around and searchable for many years, to combat Truth Decay. Seemingly innocuous inaccuracies can develop lives of their own, and seem to spread much faster than accurate facts.

I'm sorry that my post offended you.

- Eric

mrolds69

We are good, I'm still learning, too! The t-stat increase info was related to efficiency, mpg's and modern cars and sensors. My mind is a jumble of info!

MDchanic

And that is all true. In general, 195° is probably the best temperature for most engines most of the time (though I run a 180° thermostat in mine to reduce the likelihood of detonation).
That is all a different discussion, though, other than to say that, all other things being equal, running a cooler thermostat will not in any way improve the functioning of a poorly functioning cooling system, although some seem to believe that it will.

- Eric

DJS70cutlass

Thanks for the responses guys.......its much appreciated! So does anyone know for sure if the alt has to be relocated? That sounds like an awful lot just to run a shroud. I kinda like my passenger side alt haha And yes the overheating in traffic has been a problem since the day I bought the car.......it was completely stock at that time. I only noticed the problem when I added a temp gauge..........prior to that you'd have never known cause it RARELY gets hot enough for the hot light to come on.

455man

DJS70cutlass have you driven the car with the shroud on it even thought the fan is too far inside? Did the shroud make any difference in the temp? I know having the fan placed at the right place pulls more air, I was just wondering if the shroud helped any with the fan in the wrong location.
Would 40 yrs of calcium/lime deposits inside the engine make it run hot at an idle? I'm assuming this is a stock engine other than the intake.

DJS70cutlass

Well that's the whole issue......the fan hits the shroud so badly it'd destroy itself in short order if I actually started it. And there isn't any crud in the motor.......it was spotlessly clean inside when I changed the intake. Oil pan was clean as well.

lunaboy

before changing pullies and water pump, maybe get the larger 71 72 fan shroud and I have a clutch fan for that. I also have a small dia toro clutch fan that might fit your existing 70 fan shroud without hitting. if you want to do the complete change -over. I have plenty of 19 in 66-70 fans and stock pullies.

Allan R

No, you don't have to relocate the alt. You will have to change the water pump, power steering and crank pulley though. This from the 1970 Cutlass Assembly Manual

DJS70cutlass

Do you think I'd be better off going back to a 180? I only put the 160 in there cause I thought it'd run cooler

DJS70cutlass

Oh ok haha I had that pic right in front of me.......thanks a lot!!

MDchanic

Personally, I'd say Yes. The engine was designed to operate at about 195°, and will be most efficient and most durable in that range.
In my own case, I chose to go down to 180° because of my own paranoia about running a 10.25:1 engine on modern gas. I use an effective octane booster, but even so, I've had an engine that self-destructed because of detonation (which occurred during its time with the previous owner, of course), so I'm unusually wary.

- Eric

DJS70cutlass

Interesting Joe.......so your saying just bolting on a new clutch and fan assembly will put the fan at the rear of the shroud like it should? AND not hitting the ps pump shaft? Is this the fan I need? (if I decided to buy a new one)

http://www.opgi.com/cutlass/1970/coo.../fans/C980305/

DJS70cutlass

Now that's what I want to hear!! So that's the fan I need? I could definitely buy it......it is really close to me too. Where would I find the Hayden clutch?