Radiator Problems

Looking for some input on my issues with a rear mounted radiator that I have.

The motor is a 1969 Oldsmobile 350. #7 Heads

I have a 4 Core 4" Aluminum radiator mounted with a electric fan with I believe 2500 CFM.

1 1/2" Copper Pipe both ways and rubber hoses connecting them to the block and the radiator.

I have only had the chance to drive it around the yard because I don have insurance on it yet,
granted I am pronbbaly going 10mph if that, It starts to creep 160 180 then 200. and go to like 225
when im at a stop.

My fan isnt coming on. I dont know if its a relay or the sending unit. It usally comes on at 185 and off at 175.

I am hoping that when I get it on the road it will cool itself off along with the fan and the air from moving.

But If anyone has any input please dont be shy to say.

Thanks

 

It looks to me like you are going to need a very good fan and shroud to make that work. Wire the fan up to a hot wire until you get it figured out. good luck Gary

 

..and have a pro look at the rear suspension. At least one item is really wrong there, and I can't see the rest.

 

so, even if you are moving faster how will fresh air get to and through radiator? plus, where will hot air exit? better sort out fan problems before running again. so, is fan pusher or puller? have a full shroud? yep, better rethink your rear suspension set up too.

 

that thing sure looks like a ratrod

 

I always thought the radiator went in the front of the car.

 

Leave lots of room for those tires to move side to side, with that panhard rod at such an angle its going to dance like a cat on ice.

 

As for cooling, that radiator wont get squat for airflow the way its set up.

 

What are you building? From the rear cooled cars I've seen, you're going to need some serious ducts/vents a serious fan and perhaps a bigger radiator. If that's a P/U bed in the pics, cooling is really going to suck if it's covered.

And that panhard bar looks... odd. The tiny brackets attaching the front of your rear radius rods have "born to fail" written on them. Could they be mounted more securely?

 

The quick answer is to get your fan running. Hot wire it through a relay as a test and get rid of that temp sensor.........we have had nothing but problems with them and just use a switch now to control ours.

I also suspect you are not getting the cooling system full of coolant. Rear mounted radiators are a bear to purge of air, you have to get a bleeder at the highest point and that is usually on top of the intake manifold, but hard to tell in your pictures what the highest point would be.

A little air in the system can cause huge problems. One man told me he had to pick up the rear of his hot rod with a bobcat so the radiator was high enough to purge of air. He said it ran cool after that.

Don

 

I bet your water pump is having a hard job moving the coolant such a long distance,there will be hell of alot of resistance from the coolant and what the others are saying.JW.

 

Looks like an Old Skool Rodzzzzzzzz tech article waiting to happen.

 

I had a guy that builds street cars and sprint too and he did say that the bar was at a high angle. But the frame is narrow in the rear. That's the most horizontal that we could make it.

 

Its NOT going to work....accident looking for a place....IMHO

 

Please post pictures of the completed truck....I need to see how the radiator sits in relation to the bed to help figure out your cooling issue.

If that's a multi-row radiator, then mounting it backwards like you did will have some negative effect on it's cooling effectiveness.

 

How about a photo of the engine installed,you have a lot of copper pipe that absorbs a lot of heat,,add to that the headers and exhaust will be close which will also add to the already over heated system.

You are going to have to move more air through the radiator and probably speed up the water circulation.

There is the possibility it will never run cool. HRP

 

I would build a higher bracket off the rear end to get the panhard bar level. I don't see any way to make that rad setup work right.

 

I don't know what brand of fan you plan on running. You might want to look at a single electric fan from a mid 90's for tbird or cougar. They are a two speed fan and pull more cfm than any other fan out there. I think that would cool it.

 

Geez Louise, why the rear mounted radiator? Just because you can doesn't mean you should. Is this an attention whore RR? That whole thing is a friggin nightmare....