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So my '70 Cutlass 455 is running a bit hot. She's fine until I get stuck in traffic and then she starts warming up, and even when we get on the interstate, she doesn't cool down, she just keeps getting hotter.
Fan clutch seems to pass the spin test and I could just order a big monster BeCool 4 core and replace the water pump and fan clutch while installing it, but I am curious how a guy would go about just identifying the issue and fixing only the problem part. Eventually I am going to rat this thing out and will need the big radiator, but I would like to learn to diagnose and repair the problem.
So, to be specific about the problem, I run around 180-190 for a while, but even on long straightaways going 45 or 50 I start moving up to 190 and eventually 205 or thereabouts. Nothing cools her down but shutting down and waiting.
What do you guys think I should do to test the various cooling components and ID the problem child?
Not being there to diagnose it, I have no clue. How big is the radiator? 4 core? How old and gunky? Is there air trapped in the system? The questions are endless. I suggest a search on this as it has been discussed ad nauseum. Myself? I am running a Be Cool aluminum with twin Spal fans. The car runs at 180 even on days like today when it was near 100 degrees.
When the temp goes up on the highway, what is the engine RPM?
I ask because my car will increase to 210 or more at 3200+ RPM in the summer 115º temps (AC on), but if I back off to below 3000 RPM the temp comes down below 200. It's not that there's anything wrong with the cooling system, merely that higher RPM generates more heat that the cooling system must get rid of.
If your torque converter is a higher stall speed it can generate heat in traffic.
Check your timing.
Are the plugs correct for your application?
While cold , squeeze the lower radiator hose to see if it has the spring in it.
Look in the radiator with cap off when you first start the car. Do the tubes look heavily corroded or clogged? The water should start flowing as the engine warms and the thermostat opens. If the flow looks weak the radiator may be clogged.
Is there a lot of crud in the fins of the radiator that would block air flow?
Are the radiator side gaskets between the radiator and core supports in place to direct air thru radiator?
I finally put on a FlowKooler water pump and a high flow thermostat and finally problem solved.
I'm sure I missed something but it's a start. Search past threads for more.
Mine did same as you describe. Heated up in traffic and even on highway.
Last edited by Gary M; June 12th, 2016 at 09:39 AM.
z11375ss has a good setup. If you check his cool video you'll see the only heat problem he has is with his rear tires . Good problem to have. If your going to rat it eventually looking stock may not be an issue.
These cars didn't have aluminum radiators or electric fans when new, yet didn't overheat. Figure out what is wrong before throwing money at new parts that may or may not fix the problem.
Agreed. I through lots at mine before finding it had a no-a/c pump on it.
Is 205 too hot though? Does he really have an issue if 205 is acceptable?
What else can he check?
Is the cap good?
Is the gauge correct? Check with a second gauge or temp gun.
OK, those are some good suggestions. I figured this topic has been covered here as most probably have, but hey this isn't an archive right?
I'm mostly curious how a guy goes about determining when a water pump is bad or how to tell when a radiator needs to be replaced. Or if there is air trapped in the system, how does a guy purge it? Part of the fun of owning a car like this for me is learning to do these things.
I was already thinking along the same lines Gary, last night I priced the FlowKooler water pump and high flow thermostat. The radiator is a good bit more money but I don't want to have to always be concerned about running hot. I realize that 205 isn't boiling over, but it's too close for comfort for me. I have this car so I can load up all my female friends and go joyriding far from home on weekends. I'd like to know that the car can keep a steady temp before doing so. Every old car ( '73 Challenger, 70 Super Bee, '74 F250, etc) I've ever owned ran dead steady at 180, so I see no reason why this one shouldn't also.
Glad to see someone is using electric fans, I've always been curious how those work on old iron. Man z11375ss that engine is beautiful! Well done. Gave me some inspiration to get my compartment neat and tidy like yours.
Thanks in advance to everyone for any further advice!
OK, those are some good suggestions. I figured this topic has been covered here as most probably have, but hey this isn't an archive right?
First, are you coming to our Capitol City Rockets club meeting at Kilroy's Bar and Grille in Springfield at 1:30 today?
Second, unless the impeller has sheared off the shaft, the water pump will NOT cause an overheating issue. Far too many pumps have been replaced for no good reason. When a pump goes bad, it's a bearing. You'll know this by the stream of coolant from the weep hole at the bottom of the pump snout.
Third, back to my question: are you running ported or manifold vacuum for the advance? Olds used a thermal vacuum switch on cars with ported vacuum to advance the timing and cool the motor if the car started running hot.
Distributor is stock, just replaced all those components, timing is 9 degrees BTDC. Not sure Joe about the manifold. It's an Edelbrock and the vacuum line goes from the (Edel also) carb straight to the advance on the distributor. Not sure about the stall converter either but assume it is stock, the car wants to surge forward with even a very light touch on the accelerator when I hold it with the brake.
To tell if you have manifold vacuum hooked to your distributor, just pull the line off the vacuum advance at idle and see if there is vacuum at idle. Also looking at the carb, if the line is hooked to the passenger side of the carb it's ported, drivers side is manifold.
I'm mostly curious how a guy goes about determining when a water pump is bad or how to tell when a radiator needs to be replaced. Or if there is air trapped in the system, how does a guy purge it? Part of the fun of owning a car like this for me is learning to do these things.
As Joe said, the water pump either works or it doesn't; there's no in between where it may pump less water than it should.
For the radiator, you can use an infrared thermometer to measure the temperature across the face from top to bottom to see if there are any areas that are cooler than others that would indicate restricted flow.
On this type setup there isn't much area for air to get trapped in the system. Top off the radiator, run until the engine is hot, then top off again after it cools down should be all you need to do. Any air will get purged during normal operation.
I know this will open a can of worms. What thermo are you running? If a 160 and the car will operate at 160-170, you get a 25 degree rise in operation then your at 185-190.
So I got some really helpful information from the guys that attended the Capitol City Rockets club meeting yesterday, Joe's level of knowledge is truly impressive.
So the manifold does have the thermal port but it isn't hooked up so I'll need to find out how to do that, assume I will need to find a vacuum diagram but that shouldn't be too hard.
It was hot yesterday and the car just kept getting hotter as I rode down the interstate and was nearing 220 when I got to the club meeting which was only about 15 miles from home, 10 of which I was loafing along on the interstate.
So, I suppose I could replace the thermostat and cross my fingers and hope the cheap fix is the issue, but it sounded like most of the club guys yesterday think the radiator is the problem.
Someone suggested an easy way to purge the system by doing what you said Kenneth and do so on a hill. My driveway has a sharp hill by the street so I can do that easily.
I have to say that John's car looks beautiful. I love the blue color.
The engine is an early 455 block (sans serif "F") with J heads, a Performer, X/Z exhaust manifolds (that's the 73-74 X manifold that is similar to the W manifold), and an E-brock carb. Obviously pieced together, so you don't really know what's been done to it. The radiator is far from new and could be an issue.
I can confirm that the vac advance is connected to the timed port on the E-brock - the one on the passenger side per this photo:
The thermal vacuum switch on the intake looks like this one. Note that the ports are labeled "D" (distributor), "C" (timed carb port), and "M" (manifold). Simply connect the vacuum advance hose to the D port, the timed carb port to the C port and a manifold vacuum port to the M port. Note that your carb has a manifold vacuum port on the driver's side, per the photo above. It currently has a cap on it.
Try hooking you vacuum advance to the manifold vacuum port on the drivers side of the carb. You'll have to adjust your curb idle speed lower when you hook it up.
Try hooking you vacuum advance to the manifold vacuum port on the drivers side of the carb. You'll have to adjust your curb idle speed lower when you hook it up.
We had that discussion, and the TVS will do the same thing without having to adjust the timing, but John's overheating happens at all speeds, not just near idle. On the freeway, the throttle is open far enough that ported and manifold vac are the same. That's why I came to the conclusion that it's probably the radiator (combined with the apparent age of the three row radiator currently in the car).
I'll also add that there is very little resistance from his fan clutch, which makes me think it is not engaging properly.
Edit: I should also add that the car does have a correctly-fitted fan shroud.
So I hate to just buy a $550 radiator without being sure it's the issue. I wonder what the odds are that it's a sticky thermostat? Or the fan clutch? Or both?
John you dont need a $550 radiator. I would replace the fan clutch with a HD cooling one, replace the thermostat with a 180 degree one since you have to drain coolant anyway for the radiator, remove heater core hoses and back flush it(again since system is open) and then swap in the radiator. If it were me I'd upgrade to a factory 4 core style but that requires new saddles and top plate.(if not in a hurry you can buy those online from the olds venders) Autozone is running their 20% off online special again and you can order the A161 which says its for a/c or non a/c. Its 1 core aluminum core with plastic tanks. The A165 is the 4 core copper/brass like factory. The B351 is a 2 core and you dont want that one.
Before I would buy a new radiator, I would pull the one you have a take it to a good reputable radiator shop. They should be able to flow test it and rod it out if necessary and if the core is not rotted. As Joe mentioned earlier, these car did not come with aluminum radiators new and did not overheat. Is there a possibility of a blown head gasket.
Before I would buy a new radiator, I would pull the one you have a take it to a good reputable radiator shop. They should be able to flow test it and rod it out if necessary and if the core is not rotted. As Joe mentioned earlier, these car did not come with aluminum radiators new and did not overheat. Is there a possibility of a blown head gasket.
This may be the one time when an aftermarket aluminum makes sense. The car is set up for a three row radiator. The BBO apparently is a swap. Short of changing the radiator saddles for a four-row, the aftermarket aluminum will fit the stock saddles and provide the added cooling of a four row.
I'll add that if you do want to have your old radiator checked out, Loopers Servicenter in Rockville is one of the few old-time radiator shops in the DC area.
There is a recent thread on radiators. Rock Auto has a four core for $59!!! 71 455 Cutlass/442. As noted in the thread the 71 has a different size lower hose--smaller it seems at 1 7/8 versus 2 1/8. This could be solved with a 71 water pump.
I just bought this stuff at Rock Auto. New water pump, new cap, new Hayden fan clutch, 3 thermostats 160, 180, 195, four core radiator and a high volume Airtex fuel pump. $195 including shipping. What a steal!
I am with you on wanting it cool. Can't stand it when the temp creep starts--180, 185, 190, 195, 200, 205, 210... going home NOW. If Joe says the radiator had crud in it, it would be gone to the radiator shop or replaced. You will have the four core insulator issues to deal with if you buy the $59 radiator at Rock Auto, but in my opinion, worth the trouble for a COOL 455.
Can't remember where I read it, maybe it was Bill Travoto's book on high performance Olds engines. The story he tells is dyno testing a big block and he started to notice the bottom hose collapsing regularly as the RPM's went up--thus the spring in the hose. Worth a check as someone else has noted.
Last edited by David DeCan; June 14th, 2016 at 07:35 AM.
There is a recent thread on radiators. Rock Auto has a four core for $59!!! 71 455 Cutlass/442. As noted in the thread the 71 has a different size lower hose--smaller it seems at 1 7/8 versus 2 1/8. This could be solved with a 71 water pump.
Have you received this radiator? The photo shows an all-metal tank, but the "Info" page for the item talks about plastic tanks. If it's all metal, I'll buy one at that price.
You can fix the hose size with a reducer bushing. Gates P/N 26392. Slide this into the end of the radiator hose then slide it over the radiator barb.
Nice on the bushing. The guy who made the post, said the radiator arrived with metal tanks. It was a recent post on 4 core radiators from Rock Auto. Some of the folks replying to the post were buying multiple radiators. It was a close out.
Nice on the bushing. The guy who made the post, said the radiator arrived with metal tanks. It was a recent post on 4 core radiators from Rock Auto. Some of the folks replying to the post were buying multiple radiators. It was a close out.
Kewl. Got two on the way at that price. Even with $30 shipping for the pair, it's a steal.
"I did buy 2, Bought 1 to make sure it was what I thought it was (brass/copper 4 core) then I ordered another as a back up. You never know what could happen to a radiator.
Mark"
Classic Olds is going to sell them out. Going, going, gone!
well I purchased two as well, Although my Car is a manual, I guess there should be no issues, As my car didn't have a factory 4 core, I will need to get new saddles and a new top plate? and what about the shroud? is it different? And pardon the stupid question is there a repo shroud?
I was going to go for an aluminum Radiator, but this was too cheap to pass by, apparently there is only 2 left now.
June 11th, 2016, 07:18 PM
. Good problem to have. If your going to rat it eventually looking stock may not be an issue.
