Overheating (65 Riviera)

[joeinbcs]

I bought my car in San Antonio about a month ago and drove it back to my home in College Station (about a 3-hour drive), followed by a buddy in case of problems. The car overheated twice on the way. Each time I stopped immediately and checked the radiator (carefully). Plenty of antifreeze, but I let it cool off and topped it. I had the thermostat changed when I had a tune-up, oil change, etc. I was told by the PO that the car had a sticky thermostat. Seemed to run cool enough after that.

Today I took it to a car show about a 15 minute drive away. No problems on the way over, but as I dropped of a buddy on the way home who lives near me, the hot light came on.

I tried to find some direction on where to look next, and found the following from a discussion of Riviera's:

ENGINE: Overheating is the most frequently reported problem with early Riviera engines. Reasons include partially-blocked radiators and drag from or failure of the clutch-activated engine fan. The fan itself should have seven blades and when spun by hand should only revolve once or twice. If it spins freely, the clutch unit in the fan boss needs replacement. Oil pump wear will produce oil aeration and low pressure in early cars.

My fan does not spin freely, so I guess the clutch is not the problem.

Maybe a "partially blocked radiator" ? Any advice on how to tell if this is the culprit?

Any other tips on where to look to solve this?

Its over 100 here today. Is this too much to ask for a 45-year old car?

Thanks for any thoughts! Joe

[tim63riv]

Joe,

One area of the cooling system that gets over looked a lot is the radiator itself. You must have excellent contact between the radiator tubes and the fins. If the radiator fins are loose they cannot conduct heat away from the tubes and the engine will overheat.

A good friend of mine lived in Phoenix and all the car guys he knew used a radiator called the Desert Cooler. The had very high fin count per inch which equates to higher area for thermal transfer than other radiators.

Most radiator shops have a infra red thermometer that will tell them the difference between the temperature of the radiator inlet and outlet and by knowing that temperature they can give a pretty good idea about the efficiency of your radiator.

As far as a 45 year old car having overheating issues, with the new technology available now they shouldn't have any more issues than a modern car. Just make sure that the cooling system is up to the task!

HTH,

Tim McCluskey

[gungeey]

How old's the antifreeze? Pretty easy to see if rad is clogged, just leave cap off and get up to operating temp, should look like a quiet river flowing in there...not white water rapids and not a stagnant stream. The clutch fan should be harder to turn when engine at op temp than at cold...A/C blasting? Poor tune up/low idle?

There is also a new hi-po antifreeze out that has a higher boiling point, check your auto enthusiast mags. Steve

[joeinbcs]

Thanks, Tim...I guess I need to pay a visit to a Radiator shop. Joe

[Guest msht9o]

Another help might be if your car is a non a/c car it more and likely does not have a fan shroud. That is a good investment if you do not have one. That and a four core radiator seems to have helped me quite a bit.

[Jim Cannon]

Your radiator is probably clogged. In Texas, if you re-core it, put a 4-row core in the radiator.

Regarding fan clutch, when engine is hot (driven 20 minutes or more) and you rev the engine (not in gear) the fan should ROAR. If it does not, your clutch is bad and needs to be replaced. They don't cost that much and are fairly easy to replace, so when in doubt (as in you don't know how old it is) replace it.

Even at highway speeds I hear my fan clutch engage sometimes when the A/C is on.

[Guest simplyconnected]

Save your money and buy an electric fan. They pay for themselves in no time because they only run when they need to. eBay has 16" fan and controls kits for about $50. They can either mount as a push or pull fan. I just bought two, one for my '59 Galaxie and the other for my '55 Ford Customline.

Resd-up about extra rows of cores. They sometimes get in the way of airflow. If air can't flow, heat won't transfer.

Be sure your radiator cap holds the proper pressure. More pressure raises the boiling point of your coolant about three degrees for each pound of pressure. Ex: 7# X 3 = 21* At sea level, 212* + 21* = 232* boiling point (no longer 212*). My wife's Intrepid has a 16# cap...

[jrbartlett]

As current owner of two 66 Rivieras, plus a new '66 back in the day, I can assure you that overheating was never an issue with these cars when they were new, or today when they have good, clean radiators, operating fan clutches, etc. Even during the current Texas heat wave. I drove one last week in 100 degree weather, in stop and go traffic in Houston, with the AC on, and the temp guage never got beyond half-way. Normally, it's less than half-way. I think you need to look at your radiator and have it rodded out, or re-cored. You don't need an electric fan. But first, you might get one of the infrared heat sensing guns and take an actual temparature reading to ensure that your temp sending unit and guage aren't malfunctioning.

[Desmc14]

My car sat for almost 14 years.... once running again it started randomly over heating... changed thermostat and continued randomly over heating... took it to a shop which tested it using a infrared gun... temperature throughout the engine block was 'normal' and not over heating... it turned out to be the overheat sensor was corroded from sitting so long... $12 part solved the issue

Good luck!

[joeinbcs]

Ok....thanks for all of the great advice.

My local O'Reilly's had a fan clutch and it looked to be a job even a guy of my modest mechanical skills could handle. I decided to start here because it is the cheapest fix...if it works!

For some who have contributed advice, here are a few details. My car does have A/C, and you'd better believe I was using it yesterday. I just had all of the fluids changed and a tune-up, new plug wires, etc. I did check and the antifreeze seems to "run like a river" when the cap is off and car running. Not sure if this means I don't have a partially blocked core or not, but, as I said, I thought I'd start with the easiest thing first.

Which brings me to a question. When I removed my fan, I noticed that it had only 5 blades. From my searching around, I thought the fan was supposed to have 6 blades? Could this be part of my problem?

And, as for the new fan clutch, it came with locknuts, which do not fit on the studs..only room for the nuts. Is this a problem? Do I need to torque the nuts, or is tight good enought?

Thanks again for all the help, Joe

[RivNut]

5 blades is correct. You'll also notice that they're not placed symetrically around the hub of the fan.

One thing you could do that no one has mentioned yet is to get yourself a mechanical temperature gauge and put the sender in place of the OE sender that's in there now. This will give you an actual temperature reading rather than just a "hot" light.

Make sure that the fins on your radiator AND the a/c condenser haven't been flattened out by some guy with a high pressure washer. If they're bent over and there's no place for the air to flow past the cooling fins, there's no cooling. You'll have to pull the radiator to check this, but it would be worth your time to make sure there are sufficient air passages in both the condenser and the radiator.

[Airy Cat]

I have had at least 6 1963 - 1965 Rivieras and they all ran hot because the radiator does not have enough surface area. It's too small. The best radiator I found for it was that Desert Cooler from Phoenix. Also, Rivieras need 100 octane fuel. That crap they call premium fuel is only 91 or 92 octane and that will make your car run hotter. I can't even start my bar-b-cue on that crap. I run 100LL Av gas in my 60s Buicks.

[Jim Cannon]

Joe-

My '63 has 5 blades. I don't know what a '65 has (but I suspect it is the same).

I forgot to put in my previous post: your new fan clutch MUST have the small coil spring on the front face. If it does not, take it back and exchange it for the more expensive one that does. I can provide part numbers if you need them.

Use torque values in the shop manual to get it right. Use same nuts, bolts, studs, washers as you had on the old fan.

[joeinbcs]

Thanks for all the help on my overheating problem. I replaced the fan clutch (with the small coil on the face), and took it to a car club meeting last night. No problems so far.

I'm thinking that it might not be a bad idea to take it to a radiator shop and get an opinion on whether I need to have the radiator cored...before the hot light comes on again.

I won't be driving the car often, and don't plan on any long trips, but I still want it to be sorted out and capable. Thanks again to all for your interest and advice. Joe

[RivNut]

Joe,

It might be less expensive and just as effective to have the radiator shop sweat the tanks off, ROD out the tubes, straighten the fins, and reattach the tanks. I did that to the radiator that's in my '64 and I've never had a problem with it. It was actually an extra I had done when I did the one for my '63. You should have seen the one it replaced. We took the tanks off and the tubes were only about half the size they should have been. Besides some fins being bent, lots of fins were just plain missing. What a difference a "clean" system makes.

When the guys who owned these cars originally were driving them, they weren't adding 4 core radiators and electric fans. They were new, clean inside, and worked well. I'm sure that the engineers at Buick put a lot of time and study into what it took to keep this engine cool in all weather conditions.

I don't operate as well either as I did in 1965. Lot's of difference between an 18 year old body and a 62 year old body. My doctor and my mechanic both know me on a first name basis and cash my checks regularly.

Ed

[Jim Cannon]

I know several guys in Texas that have put in new 3-row radiator cores and still had overheat problems in the summer with A/C on.

It is on that basis that I recommend you go to 4 rows if you are putting in a new core.

I think the R-134A puts a higher heat load on the cooling system than R-12 did.

As mentioned by others, it may also be the lower octane gas used today.

[Guest musclecarfan65]

hmmm ... maybe your carburetor/engine runs too "lean"? most of the times the gas which does not burn works as coolant by carrying out high temperatures.

that's why it's better to run more on the "rich" side than on the "lean" side.

as far as i know that is what engine engineers also normally did when developing carburated engines.

this is based also on an experience a friend of mine made. he bought a completely restored 70' HEMI 'cuda. after driving some kilometer´s the engine was broken (valves, pistons, block, etc.) because the cylinder head gasket was burned away. they found out that the engine was running too hot because the 2 carburetors where way too lean ... the dutch restorer did not test the adjustement of the carbs :-( ... very expensive

[TexRiv_63]

I installed a Vintage Air AC system in my 63 to replace the non-working factory air setup. everything on the car was stock with a recently rebuilt 3-row radiator and a retrofitted overflow tank. I was all ready to go to an aluminum radiator, electric fans, 160 stat, etc. When I talked to the shop that sold me the VA system they said not to change a thing, the factory AC setup was more than adequate to handle the heat. They said what has been already stated by others, obviously all the components have to be in good shape, clean, and working correctly. A shroud is very important and you should add insulation around its edges to keep underhood air from being drawn in. The front-to-back fan placement in the shroud is also very important, the blades should be half in and half out of the shroud opening. (This can be screwed up by having the wrong water pump installed.) I took their advice and installed the system that way and NEVER had overheating problems in 3 years of Texas driving with the AC blasting. One thing about the nailheads, they do run hot, my mechanical gauge showed 210 to 230 in the worst of summer but it never boiled. Full disclosure - my car was not a daily driver, usually 2 to 3 times a week, both freeway and local roads. I did always worry about getting stuck in freeway traffic jam, the ultimate cooling sysytem test, but never had it happen.

One other thing - if your fan clutch is working properly you should hear that fan roaring when you take off after sitting at a light in summer traffic. The roar will die out in a few minutes as the engine cools a little and the clutch loosens up. If you don't hear the roar your clutch is not right.

Good luck!

[DrP]

Jim

I'm replacing the fan clutch while I have the radiator out. What is the part number for replacement? I have $65 quote but I'll need to check against your part number as I don't want to put in "junk" parts. Tnx

Dale

[Jim Cannon]

Jim

I'm replacing the fan clutch while I have the radiator out. What is the part number for replacement? I have $65 quote but I'll need to check against your part number as I don't want to put in "junk" parts. Tnx

Dale

The part number you need is Imperial #215049.

[DrP]

Grateful to you Jim.

Dale

[Guest clamshells]

I have seen many Rivs without fan shrouds and per my experience wouldn't run without one. My 66 had issues in the summer with the AC on. 3 thermostats, 2 fan clutches and a 4 core later I solved that problem with a electric fan and swear the car ran better without that 8lbs fan & clutch. Sure it isn't original equipment, but a nailhead rebuild is pricey and over heating is also very hard on automatic transmissions.

[Mr Riviera]

Heat is the early Rivs worst enemy . First think you need to know is if you really have a problem . Install a mechanical gage somewhere . I put mine in the clock . You can leave the original sending unit (light) and install the mechanical sending unit in the rear of the drivers side head - same location , plug , as the original but on the opposite side and in the rear . It may indicate a little higher temp there but safe . It is common for the original light to come on early so you really need to know what the temp is . The fan shroud is a good idea also - for cooling and safety .

[Guest Riviera Swede]

When you have a new heater core mounted flush the engine veery carefuly. When you mount the radiator, install a heat resistant fine mesh net on the upper radiator boss . Then you will get clean the net several times when you started driving the car. When the filter does not become clogged anymore you can remove the net. Failing to do so may new radiator become clogged again. Another error I had on my 65 a is that the fan was sitting backwards mounted when I bought the car. Check this.

Riviera regards from Sweden