Hi all,

After many years, my L88 is recently overheating in city traffic only. My radiator is NOS, I think it's the high-capacity that came with the big blocks back then. My fan has 5 blades and sometime in the past I did change the fan clutch.

So far I have pried the fan clutch, based on this post ( https://www.corvetteforum.com/forums...lutch-fan.html ) and shortened the brass rod under the bi-metal plate. Now the fan doesn’t spin more than half a turn, when I shut the engine when cold (I wonder if I over did it), but the result is not much better.

Next I plan to flush out the system with radiator cleaner.

Next is the fan: my question is, will going from a 5-blade to a 7-blade make a substantial difference?

Now on the water pump. It has been in there for decades and I wonder if with time they get corroded and move less water, but I wont know till I remove it. If it is bad, I'm contemplating a High Volume one, even though I read so many pros and cons about them. As I am for originality, are there high volume pumps that look like the original ones? Also I find them in two versions, Long and Short, what is the difference?

I realize that the radiator is the real way to go, and if flushing it wont help, I’m thinking of taking it to a special shop where they take it apart and do a thorough job.

So what do you guys think? Any comments will be appreciated !

 

Hi G,
L88 in Greece, very nice!

Do you think the radiator in your car is the original?

Originally 4-speed L88 cars had an aluminum radiator while automatic L88 cars had a copper radiator.

The aluminum radiator has a part number stamp and a date code stamp on the left side of the radiator's upper plate.
The copper radiators have a tag attached to their right side containing a part number and a 2 letter broadcast code.

What are you seeing on your radiator that might help identify it and give you some guidance in what you do to/with it.

Regards,
Alan

Here's an example of a restored original sb aluminum radiator.

 

a 7 blade and a Severe Duty Clutch should solve it , providing your Radiator is of sufficient size

 

I am surprised that you can drive the car in traffic without overheating all the time. The L-88's came without a fan shroud. I think if you could get one from a big block car, it would go a long way to keeping the car cooler. GM designed them for racing and not to be used in traffic. Good luck, sounds like a fun car to drive. Jerry

 

I would do the cheaper stuff first ,change the thermostat,could be just old and tired ,a little like Me.

 

I agree you must have very cool weather . I had an L-88 years ago in Virginia and the only way to keep it cool was to drive it 80 m.p.h. I modified a big block corvette shroud and that helped a little. I drove mine mostly at night and spring and fall. A.cooler thermostat is a must. Flush the radiator out and check your timing. An aftermarket aluminum radiator may help. But you have 12.5-1 compression and fuel may be questionable at best. Good luck keep us posted

 

L88's did not have a fan shroud. Does yours have a shroud? This could leadto an over heat condition.

 

In several recent posts, I have been praising the Stewart water pump.

My original LS4 would run 200/210 on a hot summer day.

My new(er) 454 wont even come close to 200. Its a stock gauge, and I'll guess to say that it runs 180. The engine, aluminum intake, and stewart water pump are the only difference... every other component is the same. Even recycled the same thermostat.

Im sure my overdrive also helps, but that doesn't really get used much around town. Im crediting the pump with this win.

http://www.stewartcomponents.com/ind...&product_id=79

For some reason this is 65-70
http://www.stewartcomponents.com/ind...&product_id=74

 

You can rebuild the bushings in the water pumps. I'm not sure about the vanes. I would pull the pump while your having the radiator serviced. Its not hard and its right there and check the impeller. Its cheaper to look and do it all at once than to have to keep pulling the engine compartment apart apart checking thing one at a time. And yse the vanes can corrode off it the improper coolant was used. And of course replace the thermostat

 

Thank you all for your kind interest! The Vettre and I go back to ’68 when I brought it over here with a 327ci 350hp small block; soon after that I got into car racing and ended changing engines and a whole bunch of racing stuff, I was younger then !

Here are the current details from what I can remember and what I can see now:

Engine 454 ci, with the second design aluminium heads, a 4160 Holley with 960cfm. At one time I had an Edelbrock Hi-rise manifold and the competition exhaust headers, but these were replaced with regular stuff so I could drive the car on the road.

Radiator: seems Aluminum,(see sticker pic) and it does have a shroud :





Water Pump: I read the short is 5 5/8’ and the long is 7 ¼ but don’t know how/where to measure so I guess I have the short. Thanks Big Block Dave for the links of the pumps, its good to know they are cast iron so they look original in case I will be needing one; cant tell though what is the difference between them, besides the shaft diameter (5/8 and ¾). Here is a pic






Clutch, Thanks Fishlayer 143, it nice to know there exists a Severe Duty one, do you have a link for it, it seems it is one of the things I will be changing for sure

Thermostat, cant remember what I have in there, it probably has aged just like me

Hope all this makes sense!

 

...

 

I didn't see anyone mention timing. Check and make sure it's still set correctly.

Also running too lean can cause over heating. Recheck your A/F.

 

water pump ID

https://content.speedwaymotors.com/A...e597482e64.jpg

http://www.roadkillcustoms.com/hot-r...#axzz4XqFDonLh

 

these ran hot when new they werent street cars
do the best you can with the cooling system
If it were mine id put a milodon 160 stat, drill a few holes in the outer housing put a flex fan on it and an electric that came on at 200 (thermostatic switch).
Some know how to make the clutches lock up earlier just dont like all that weight on the water pump snout always broke them.

 

that is not an aluminum radiator. someone just put the AL sticker on it.

When you start out the story that you have an L88, we all instantly assume that you have the original aluminum radiator and no fan shroud. That throws everyone completely off the trail and you get a lot of wrong answers to your problem.

Start with better engine pics, and that it is not an L88 and we can diagnose the problem better.

BTW - changing to a thermostat with holes drilled in it is not the solution.

I put my money on 40+ years of rust and crust in the radiator causing flow and heat transfer issues.

Bigredbrad

p.s. If it is a real L88, I would be damn careful about throwing generic speed parts at it in an attempt to solve a cooling problem.

 

Im all confused, i thought an l88 was a special chevy 427 with high compression , rad cam and aluminum heads, i thought even top shelf fellows had trouble street driving them from overheating etc,

Then i see the ops engine is a hopped up 454, so then its not a l88? Right?

 

That is a short pump. All Vettes had short pumps.

Your belts are too narrow. They should ride flush with the top of the sheaves.

 

Yep apparently everything will a big block is an L-88 these days. We should have known this thread was a farce.

 

Right!


And the OP's car was originally a small block car, too. However, I'll give him "props" for putting the big block in it....

 

So maybe he wasnt aware of it not a big deal

Love big blocks but sometimes keeping them cool is a pain