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Discussion Starter #1
I have a friend with a 1967 Chevelle that has a mild 396 big block in it. It has a champion aluminum radiator in it with two electric fans on it. I have checked to make sure the fans are turning the right way. While the car is going down the road it is wanting to heat up. He usually stops it when it gets in the 215 area. If he stops the car and lets it idle it will cool back down. It has a Vintage air front runner system on it with I'm sure a stewart water pump. The water pump seems to be circulating the water in the radiator fine. I would think the car should be getting plenty enough air going down the road to cool it. It has two gauges on it. A Dakota Digital and a Sniper coolant temp sensor. Both gauges are reading pretty close so I don't think it a gauge issue. My friend has tried several thermostats and flushed the radiator out using several different brands of radiator flush. I've been around cars all my life and what I'm seeing simply doesn't make sense. Most of the time if a car is heating up going down the road it is a air flow issue. On my 1965 Nova I can take the relay's out of my fans and it won't heat up driving at highway speeds. I've actually seen him drive up with the car running close to 220 and let it idle in my driveway until it cools enough to start cycling the fans off and on. At this point I'm thinking it must be a radiator or water pump issue but just looking at them they seem to be fine. It isn't losing water to make me think it's a engine problem and I set the timing myself so I know it's right. Anybody want to venture a guess. Mike Goble?
 

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just guessing - - - - - - - - good ' radiator hoses ' ? . . . . check the lower hose , spring "inside" .
You're right - going down th' road - - - - driving ...... air-flow should keep things cooled down (most
cooling problems are somewhat the opposite (where they tend too heat up from sitting - & cool - down when moving) .

Or , could it be somehow - sucking up the HOT Road heat , when moving . . . ? Making thing get even hotter . . . ?
Or , keeping the 'Hot Air Trapped' under the hood - - - - - (like not venting that air - out) .

again , Timing ? (something moved ? ) .

just asking . . . . . jim
 

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I haven't checked for vacuum advance but I did set the timing and I know the pointer is right. I know the distributor is advancing to the right numbers. It has a HEI distributor in it. I checked TDC and did the timing myself. Timing is actually fairly mild at 34 degrees. I can't remember what the initial timing is but when I did it I didn't see anything that concerned me. The pulley ratio is all vintage air stuff. It has their front runner system on it. Everything seems to be in order but of course you cannot actually see the water pump working but it does seem to be circulating the water all right when the thermostat opens. The thing that really puzzles me is that when the car is stopped it starts cooling almost instantly. I'm leaning towards a bad/weak water pump or clogged radiator but again, I haven't seen any signs that that's what the problem may be. The car does have a radiator fill plate between the grill area and upper radiator support so air should be forced thru the radiator.
 

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Custom Jim . . . . . exactly . . . . . thanks for the picture . (y)

Alot of newer rad. hoses that I have seen - - do NOT have those springs . . . . . thus , I have
"re-cycled my springs from my older hoses .

g2072

just another thought . . . . .

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Discussion Starter • #1 2 h ago
" It has a Vintage air front runner system on it with I'm sure a stewart water pump. The water pump seems to be circulating the water in the radiator fine. I would think the car should be getting plenty enough air going down the road to cool it. It has two gauges on it. "

Don't the "Front Runner Kits" . . . . use a ' reverse flow water pump ' . . . . . . just asking ( I don't know ) .
............ over driven ---- under driven ........... ?

. . . jim
 

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Discussion Starter #8
I honestly don't know about water pump flow but I don't believe it's reversed. I have the same system on my car other than the fact mines for a small block and his is big block. The car was bought running and the front runner system was already on it. I don't know about hoses but will check. This is not a car that see's any high rpm's. It is adult driven and generally just a clean cruiser. It does have a high gear with a four speed transmission so no excessive rpm's while driving.
 

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Could the front runner system be spinning the water pump the wrong direction? It would still appear to be stirring water around but not as much as its supposed to.
Hi Jim . . . . . I , also thought that same thing . . . . . . and worth looking at .

How you been doing . . . . ? Just Staying home around here and helping out in Diana's garden . . . . .
. . . . spell that as "Honey, sure I can do that ! " ( I need too eat ) .
Stay safe . . . . jim
 

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Thank you for those pictures . . . . Very Nice 67 .
and, I like those 67's better , nice ride .

jim
 

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Discussion Starter #12
Thank you for those pictures . . . . Very Nice 67 .
and, I like those 67's better , nice ride .

jim
We did the engine compartment for him a while ago. I think he has a Be Cool unit coming for it and will probably change the water pump while the radiator is out of it. I hate for him to just start throwing parts at it but a new cooling system never hurt anything. Will really be confused if the problems aren't eliminated. I will check the upper/lower radiator hoses. I think he's trying to get it ready for Cruising the Coast early next month. The situation does have me scratching my head a little. What I'm seeing just doesn't make sense.
 

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The nice thing about checking if the hoses have springs, or how soft or hard they might be, is you don't really have to take anything apart. With the system not under pressure and maybe with the radiator cap loose or off, if the springs are inside, then one should not be able to pinch the hoses closed by hand.

Jim
 

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True . . . . and I can see your concern . . . . having that kind of car . . . .
Plus, with those kind of : car, motor, BUILD , and details . . . . Everybody knows their 'stuff' . . . .
a very nice thought out 67 , for sure . I hope you guys can find the problem ; and, IT is strange that
there should be any 'cooling issues' with that great build . . . you guys DO Know how too get the job
done .
With that said . . . . . . . . .. could be just something ' simple ' , that is maybe getting over-looked .
Even the top Hose looks to be stock type radiator hose . . . . which should be correct , and work
properly (by all accounts) .
Like you stated early on . . . . that most cars "cool really good - when moving / driving - and have that
forced "air flow at speed" to aid cooling effect ' .

I do see an A/C line . . . . . Check the "air gap between the condenser & radiator " . . . . hold a sheet of paper in front of the condenser . . . . check for "air draw through the front system" ( I'm just asking ) .
Ask - what , is blocking the (forced) air , going or hitting the front area . . . that should be enough to cool
down the engine compartment ? ? ?

(all . . . just asking . . . What if ? ' s ) .

We all might just learn something , Keep looking .

. . . . jim

Would there be any help too install / mount - - - like a 'Go-Pro' under the hood ,
as you test drive . . . . . for some "real - time - feed-back" . . .
being that all things are / look different : sitting still vs driving down the road
at speed ( which seems to be where the problem lies ) .
again , just thinking out loud .
 

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I don't know if it would apply since it's comparing apples to oranges, but I had a 2001 Pontiac with a 3400 V6 showing those same kinds of symptoms (could idle for hours with no issue, but would overheat on the road). I had a small tear in my head gasket between a cylinder and a water jacket. Put new gaskets on it and drive it 60,000 miles until I sold it.

Have you done a compression check on it?
 

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Discussion Starter #16
I do see an A/C line . . . . . Check the "air gap between the condenser & radiator " . . . . hold a sheet of paper in front of the condenser . . . . check for "air draw through the front system" ( I'm just asking ) .
Ask - what , is blocking the (forced) air , going or hitting the front area . . . that should be enough to cool
down the engine compartment ? ? ?

Would there be any help too install / mount - - - like a 'Go-Pro' under the hood ,
as you test drive . . . . . for some "real - time - feed-back" . . .
being that all things are / look different : sitting still vs driving down the road
at speed ( which seems to be where the problem lies ) .
again , just thinking out loud .
I have not checked the air gap between the condenser and radiator. You can take a dollar bill and turn it loose in front of the grill and it will suck it to the grill and hold it. Should be plenty of air especially going down the road. You can also hold your hand after the radiator and it seems to have plenty of air getting thru the radiator into the engine compartment. I have thought about it being a head gasket issue but it is not losing any water and cools really well when not moving. I have not checked the compression. He bought the car and it has been "niced" up but we did not totally build this car. We took the engine out of the car to do the engine compartment and while it was on the stand I checked stuff like TDC, valves and stuff. It seems to be a mild 396 with a little hydraulic camshaft in it. Certainly not big HP by any means. Car really gets out and handles nice other than the annoying heating problem. We did install a Holley Sniper system on it and even the handheld numbers look great. The Sniper does not control timing. We did that manually. This has been going on for a few months and nothing obvious has come up. I do know sometimes just a little gremlin is all it takes. Thanks for the replies. Anybody have any more ideas pop up please share.
 

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You stated in your initial post that the car will cool back down at idle, does it maintain the temp at idle correctly?
If it does then the cooling system is working, rad, cooling fans, pump, etc
The problem can be either the cooling system not functioning correctly to remove the heat, or you are making more heat while driving than the cooling system can take away.
I would be looking at the timing curve, maybe not setup right and at driving speed the timing is off. Get a timing light and check it.
 

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Is the Vintage Front Runner Kit a single belt? If it is would that not require a "reverse" turn water pump? I would make sure you have the right type pump before changing radiators and such.
 

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Discussion Starter #20
You stated in your initial post that the car will cool back down at idle, does it maintain the temp at idle correctly?
If it does then the cooling system is working, rad, cooling fans, pump, etc
The problem can be either the cooling system not functioning correctly to remove the heat, or you are making more heat while driving than the cooling system can take away.
I would be looking at the timing curve, maybe not setup right and at driving speed the timing is off. Get a timing light and check it.
You can be driving down the road and it will start getting hot. You can drive it in the driveway and let it idle and it will start cooling back down sitting there idling. It will cool until the electric fans turn off and will sit and idle until it runs out of gas all while cycling the fans off and on. I have rechecked the timing a couple of times thinking I had to have missed something but everything is working like it's supposed to. Initial timing is fine and as the rpm's go up it brings in total timing to about 34 degrees. I have not checked the exact rpm total timing is achieved but I've had the light on it a half dozen times with nothing standing out. Plugs do not show to be lean and the hand held doesn't show it lean either. I have actually ridden in the passenger seat watching the hand held and it doesn't show it lean going down the road. The thing is I cannot figure out why it is building more heat than it can take away while going down the road. I know this car shouldn't have heating issues especially while running 55 mph going down the road. He has tried several different thermostats including the stewarts with the holes in it and it's no different with a 160 or a 185 thermostat.
 
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