c3 "hot"?

**Chuck R.** · January 23, 2006, 11:03 AM

Re: Just guessing, but

How old is the water pump and what size?

It just may be a lower voluum style pump that can't handle the extra radiator capacity.

You might also have collapsed or collapsing hoses.

Hope it's a quick fix.

Chuck

**James A. Lloyd Jr.** · January 23, 2006, 04:29 PM

Re: Just guessing, but

original water pump, hoses check out ok top hose is new.

what water pump should i use if that is the case

**Daniel S.** · January 23, 2006, 06:19 PM

Re: Just guessing, but

First thing I would do is confirm that the temp guage readings are correct via an infrared therm.
If the temps you indicated are actually correct, 210 is not all that high.

Also, as indicated already, make sure rad hose is not collapsing.
Shroud should be in place and sealed correctly so the incoming air will pass through the radiator not around it.

It is possible that the "fairly new" radiator is not allowing the coolant to flow optimally when the vehicle is up to speed on the highway.
I had a similiar problem with my '68 L71 and a new radiator cured it.

**Gordon Peterson #4961** · January 23, 2006, 06:45 PM

Re: Just guessing, but

Good suggestion from Dan re. the infrared thermometer. Could be your gauge.

Here are couple of things I've learned. Don't worry about it until it heads for the end of the scale - THAT indicates a problem. But 210? All day long - np. I used to worry when it hit 185, but turns out that was unrealistic.

Here's something interesting - check your antifreeze ratio. Yeah yeah everyone recommends 50/50. But antifreeze is not the coolant here, water is. I changed my ratio to be 60/40, more distilled water than A/F. And this made a difference - it consistently runs cooler. And it's still good to -25 degrees (my garage occasionally dips into the +20's). If you live in a warmer climate, perhaps play with 70/30 (still good to -15)?

Water Wetters? Hmmmm, IMHO the jury is still out on those. There are a lot of claims.

Pete

**Duke W.** · January 23, 2006, 08:31 PM

Re: c3 "hot"?

Lack of cooling at speed is often due to radiator heat transfer problems - lack of sufficient radiator capacity (like an improper replacement or recore), or clogged tubes.

Over the years traditional green antifreeze precipitates out a lot of salts that clog up the tubes and act as insulation, drastically reducing heat transfer performance. This can be cured (brass rediators) with mechanical cleaning known as a "rodout" or a recore if the tubes have pinhole leaks. You should always be sure than any recores have the same fins/inch count and core thickness as OE. Even if a core "fits" that's no guarantee that is has OE equivelant heat transfer performance. Once vintage Corvette-type aluminum radiators clog up, they are toast and must be replaced.

You didn't mention radiator maintenance history or whether it is OE or a arecore of replacement.

Duke

**Mark #28455** · January 23, 2006, 10:40 PM

are the foam seals still there?

My BB cars run great at 190 to 210 degrees and never overheat - even in Missouri with temp over 100. The C3 is sensitive to missing seals between the radiator and support and the radiator and shroud. If thet're missing or not sealing well then replace them. (many vendors have them, I use the ones from Dr. Rebuild)

Also, a thermostat doesn't change the maximum temp of the engine, that's a function of the engine heat production and the radiator heat dissipation. I would not recommend a 165 degree thermostat as it may not allow moisture and hydrocarbons from blowby to distill out of the oil. I would stick with the 180 or 195 as was original for your car for best operation.

Make sure your radiator is full, I believe the 1968 BB did not have the overflow bottle, so if the radiator's 1/4 down, you lose 1/4 of the cooling capacity - even a little bit may make a difference.

Hope this helps,
Mark

c3 "hot"?

c3 "hot"?

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