ye olde cooling problem 68 big block
Thread Starter
Instructor
Joined: Jul 2004
Posts: 202
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ye olde cooling problem 68 big block
Considering going DeWitts, or something like it.
My radiator shroud is...how you say? Meh. And with what they cost for a 68, I think I am better off biting the bullet. The radiator is a nice big 5 core.
The car stays at a really nice tempt right until I get on the highway...then up..up...up she goes.
My only other thought is that maybe some sort of air dam in the front would help more?
Ok, tell me what I already know...
My radiator shroud is...how you say? Meh. And with what they cost for a 68, I think I am better off biting the bullet. The radiator is a nice big 5 core.
The car stays at a really nice tempt right until I get on the highway...then up..up...up she goes.
My only other thought is that maybe some sort of air dam in the front would help more?
Ok, tell me what I already know...
Drifting
Joined: Oct 2005
Posts: 1,527
Likes: 148
From: East London/SW Essex UK
Considering going DeWitts, or something like it.
My radiator shroud is...how you say? Meh. And with what they cost for a 68, I think I am better off biting the bullet. The radiator is a nice big 5 core.
The car stays at a really nice tempt right until I get on the highway...then up..up...up she goes.
My only other thought is that maybe some sort of air dam in the front would help more?
Ok, tell me what I already know...
My radiator shroud is...how you say? Meh. And with what they cost for a 68, I think I am better off biting the bullet. The radiator is a nice big 5 core.
The car stays at a really nice tempt right until I get on the highway...then up..up...up she goes.
My only other thought is that maybe some sort of air dam in the front would help more?
Ok, tell me what I already know...
Last edited by roscobbc; Aug 18, 2009 at 05:40 PM. Reason: add text
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
I had that same problem on my 69- until I removed the front license plate and bracket. Above 70, the temp would climb until I slowed down to 40. I tried everything I could think of short of electric fans. I'll never see it run at 180*, but I'm happy with 200*.
Burning Brakes
Joined: Apr 2007
Posts: 1,028
Likes: 1
From: SOUTH ELGIN IL
Curious... I have this very problem and have posted about it several times and no one has suggested the license plate. Unfortunately, mine is not on there anyway so I don't think this is my answer but I've been looking at that license plate hole for some time and considering putting it on there to see if there's a difference. Mine is fine at low speed but god forbid I hit the hwy - as you say up, up, up.
I think I'm going to have to bite the bullet myself and get a dual fan setup and a new DeWitts.
I think I'm going to have to bite the bullet myself and get a dual fan setup and a new DeWitts.
Drifting
Joined: Oct 2005
Posts: 1,527
Likes: 148
From: East London/SW Essex UK
Curious... I have this very problem and have posted about it several times and no one has suggested the license plate. Unfortunately, mine is not on there anyway so I don't think this is my answer but I've been looking at that license plate hole for some time and considering putting it on there to see if there's a difference. Mine is fine at low speed but god forbid I hit the hwy - as you say up, up, up.
I think I'm going to have to bite the bullet myself and get a dual fan setup and a new DeWitts.
I think I'm going to have to bite the bullet myself and get a dual fan setup and a new DeWitts.
Race Director
Joined: Feb 1999
Posts: 16,978
Likes: 7
From: In Dreams There Is Truth Ohio
99% cooling problems deal with corroded radiator and defective clutch fan. Check the bottom rows for loose cooling fins...if the fins are loose, then either buy a new rad from DeWitts or have your old one recored...also check your clutch fan if you have one...the fan should have drag...if it's free wheeling, replace it.
And Yes, the front plate bracket does hinder cooling to a point...I had problems cooling my motor, then recored my rad and I'm steady between 180 in town and just a shade under 200 on the freeway with the front plate...Ohio law...have to run front plate...else I'd remove it.
And Yes, the front plate bracket does hinder cooling to a point...I had problems cooling my motor, then recored my rad and I'm steady between 180 in town and just a shade under 200 on the freeway with the front plate...Ohio law...have to run front plate...else I'd remove it.
Last edited by GDaina; Aug 19, 2009 at 09:45 AM.
Burning Brakes
Joined: Nov 2006
Posts: 954
Likes: 40
2022 C3 of the Year Finalist - Modified
Considering going DeWitts, or something like it.
My radiator shroud is...how you say? Meh. And with what they cost for a 68, I think I am better off biting the bullet. The radiator is a nice big 5 core.
The car stays at a really nice tempt right until I get on the highway...then up..up...up she goes.
My only other thought is that maybe some sort of air dam in the front would help more?
Ok, tell me what I already know...
My radiator shroud is...how you say? Meh. And with what they cost for a 68, I think I am better off biting the bullet. The radiator is a nice big 5 core.
The car stays at a really nice tempt right until I get on the highway...then up..up...up she goes.
My only other thought is that maybe some sort of air dam in the front would help more?
Ok, tell me what I already know...
If heating problem is when you stand and you going to change the radiator and stay with clutch fan and not fixing the shroud you will have the same problem.
I had the same problem with my SB and the only thing that solved the problem was big shroud like the BB and sealed every gap to the radiator.
I change before that to big rad' new water pump flex fan noting help.
Avner
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Burning Brakes
Joined: Nov 2006
Posts: 954
Likes: 40
2022 C3 of the Year Finalist - Modified
Do you have the front spoiler?, are the two holes in the front valance are open? check your water pump & you clutch fan.
If you stand and the tmp' ok I don't think the problem is the rad', thermostat or shroud.
Avner
If you stand and the tmp' ok I don't think the problem is the rad', thermostat or shroud.
Avner
Thread Starter
Instructor
Joined: Jul 2004
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Burning Brakes
Joined: Dec 2008
Posts: 971
Likes: 45
From: Middlesex NJ
Around town and idling you need the fan and shroud to pull air through the radiator. On the highway your fan and shroud are almost useless as the speed of the car is easily pushing harder than any fan or shroud could. If you are turning 3k rpm at 70 then you are asking the motor to work harder and it is producing more heat. Sounds to me like your radiator is not as efficient as it used to be or maybe your pump vane is worn down or your engine is gunked up inside. I have heard of situations where a very thick radiator will actually work against you as it is to thick for proper air flow. Also, make sure you dont have to much mechanical and or total ignition advance over 3k rpm and that your carb and fuel system is not running you too lean.
Burning Brakes
Joined: Nov 2006
Posts: 954
Likes: 40
2022 C3 of the Year Finalist - Modified
Last edited by avner; Aug 19, 2009 at 05:23 PM.
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
OE 68 BB`s are copper radiators not aluminum....No shroud is a mistake too.....Don't try to out engineer the engineers that made it, all you will do is complicate the situation. They were not made to overheat and certainly never when new so go figure....the OE stuff works...remember the BB`s were in passenger vehicles and trucks, they were not exclusive to Vettes
