Water Temp Problems

Well guys I need some help!

I got my 29 RPU on the road a few months ago and I am fighting high temp problems all the time. First of the motor is a bone stock 70 Chevy 350 with a TH400 and a 9" rear with 4.10 gears. The radiator is a new 60's Mustang unit that is about 18"x18" w/tanks. I have a 15" regular 6 blade fan on the engine side and a 14" electric fan pushing through the radiator.

First off I live in Bakersfield, CA and this time of year it is 95-100 every day. If I go for a 15 min. cruse on city streets with stops now & then the Temp will go up to 220-230 deg even with the electric fan on. Have half & Half antifreeze in the system. I have tried with and without the thermastate with no difference. The water pump is new also.

I am running out of ideas to check. WHAT'S THE PROBLEM [S

Put in a few pictures so you can see the radiator in the car.

First thing I would do is to take that grill out, I think it is blocking the air flow to the radiator. I see that it looks like a new radiator , but for what engine. There are several different Mustang radiators. You need the one for the v-8 car. Also a fan shroud might help a lot. Just my quick thoughts.

RPM said:

Also a fan shroud might help a lot.

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From the pictures it's hard to tell but it appears there is a pretty big gap between your fan & rad. I might change fans and use a shroud. But saying that, with both a regular fan and a elec fan it seems like that should be doing the trick. What thermostat are you running? And I'm with RPM, trying running without that grill & see if that makes a difference.

Toad

I think, like the others said, that you have several things going on.

1) I know some people have good reports on the Mustang radiators, but that one seems a little small to me. Is it a V8 Mustang 3 core?

2) There is no fan shroud on the backside and it does seem like the fan is too far away from the fins. Should be about 1/2 to 3/4 inch away. A shroud directs the air through the core instead of around it.

3) That screen in front is acting like blockage. Kinda like when we put cardboard in front of our radiators up north in the winter to get more heat out of a car.

Does the car run warm going down the road or just at lights?

Do you have vacuum advance hooked up to your distributor?

To give you some perspective, my 23 ran a 350 engine with a PRC aluminum radiator and SPAL 16 inch electric fan. I rarely had to use the fan even at lights, and could never get mine above 150 degrees. I had to put in a 195 thermostat to get it up to a more acceptable 170...........and I live in Florida.

How many quarts of 50/50 mix did the radiator hold when you filled it? Did you burp the engine to get all the air out? (You can do that by loosening the sender on top of the manifold until all the air is out.)

If it were my car I would eliminate that fan and spacer, put a 16 inch (or 14 inch if it will not take a 16 incher in there) SPAL puller fan on the backside, with a shroud, and forget the pusher altogether. Pushers are only about 50% as effective as pullers, and it might actually be blocking some airflow.

The more I look at your pictures the more I think it is just radiator size, it looks tiny on there.



Don

If all else fails make sure engine is not running lean or timing too low. Have found in drag racing that if it's too lean or timing just a few degrees low it will run hotter no matter what.

bgbrktracer said:

If all else fails make sure engine is not running lean or timing too low. Have found in drag racing that if it's too lean or timing just a few degrees low it will run hotter no matter what.

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I'd be inclined to look at things other than the rad too.

I used to run a '68 Nova with a 5" gap between the stock fan and the un-shrouded single core rad, and that ran cool even in the 100f + heat of the Philippines stop and go traffic.

A little car like an RPU should idle all day in traffic at whatever temp your 'stat is set to. Double check your timing, your mixture etc. Is your vacuum advance connected, working? Is your electric fan blowing in the right direction. Daft question, but it has been known....

Just a thought, I see that rad flows water from centre at the top, to the bottom corner. Essentially missing out half your rad area at low water speeds. That's why most rads run from corner to opposite corner, so you use the whole acreage. If it is out of a non-V8 mussie then it might be designed for a motor a quarter the size of yours.

Is it possible you have a water pump with reverse flow??
I have heard that some later model pumps flow in the opposite direction than the old pumps. Not sure what would be an easy way to check this, other than watching the flow of water in the rad. while running! If you do this be careful!! Others may know more about this, Just A Thought!!

BTW that looks like a V8 rad., and flowing from the center is not a problem with vertical cores!!That should give plenty of cooling to a mild 350, there's another problem if it doesn't!!
A shroud would help, and I'm not crazy about the holed grill, it has to restrict a little, if not a lot!!
Let us know what you find, good luck!!

One other thing, don't be offended but make sure the fan is on right,(not backwards)!!

RPM - Toad - donsrods - bqbrktracer - King Herald

Well guys thanks for all the comments and observations. It will take me a few days to go over the points you mentioned and I will get back to you. The first thing I will try is to remove the radiator cover and run it like that to see if it makes some difference. Tom

Tom, does it run hot going down the road as well as when idling? How long does it take to heat up?

Don

To all that have helped with input and suggestions.

Some facts: Radiator core is 2" thick, 16"H x 17"W, 6 blade fan is 3/4" from the radiator face, Vac advance is working (timing is 2deg advance at idle and goes to max retard on acceleration), starts first turn and idles at 800 RPM.

Without making any other changes I removed the radiator cover (outside shell and the metal face) I went for a 35 min ride both stop & go and open road, the air temp was about 85deg and humid. I have tested my gauge with hot water and thermometer and found that it reads 14deg high when in the 160-220 deg range. Around town it went to 190 (with correction 175) and on the open road 180 (with correction 165). The electric fan made no difference in temp weather it was on or off.

I am real happy with the results [cl and before I do any other changes I want to remove the electric pusher fan as it blocks a lot of the face of the radiator. I am sure you guys called it right when you said the cover was blocking the air to much.

Also I want to put back the 160 thermostat I took out so there is a little more restriction in the housing like it should be. May just install a re stricter washer later as you do not really need a thermostat in our area.

Tom

Glad to see you're making progress. Timing is a little low for my taste, usually run 6-8 degrees at idle with advance unhooked and line plugged(on stock engine). Also, make sure advance is connected to timed port and not straight port. Timing should advance on accel not retard.

Yep pretty smart folks on this forum

bgbrktracer -- Ok, my mistake in terminology, I had the timing at 2deg before and I reset it to 8deg before and it goes to 15+ on revving up.

Will remove electric fan tomorrow and test drive again with the same setup as today. I think we are on the right tract.

What about having the thermostat in or out? If I leave it out do I need to put in a re-stricter washer?

Tom

I would run a 180 thermostat.

old28 said:

bgbrktracer -- Ok, my mistake in terminology, I had the timing at 2deg before and I reset it to 8deg before and it goes to 15+ on revving up.

Will remove electric fan tomorrow and test drive again with the same setup as today. I think we are on the right tract.

What about having the thermostat in or out? If I leave it out do I need to put in a re-stricter washer?

Tom

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Yes the flow of water needs to be restricted, otherwise the water travels through the radiator to quickly and won't cool!! You can buy them in 1/2 5/8 and 3/4 inch size holes!! I would try a 5/8 inch first!!

rainman said:

Yes the flow of water needs to be restricted, otherwise the water travels through the radiator to quickly and won't cool!! You can buy them in 1/2 5/8 and 3/4 inch size holes!! I would try a 5/8 inch first!!

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Why not just fit a thermostat and do the job properly?

King Herald said:

Why not just fit a thermostat and do the job properly?

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Lives in Cali, says he doesn't really need one. If I didn't need it I wouldn't run it either!! Just one more thing to go wrong!

But I agree, if I ran one it would probably be a 180, and not a 160, the engine will perform better at that temp!!

Well guys I have a 160 thermostat that is new that was in there and I think I will put it back in and see if it makes any difference. With average days in Bakersfield, CA area running 85-105 for 6 months I don't think it really matters.

I do agree with (rainman) that it needs some restriction in place slow the water flow. If I don't see an advantage with the thermostat I will try a 5/8" restrictor.

I don't think that 70's 350 with lots of miles will know the difference.

old28 said:

Well guys I have a 160 thermostat that is new that was in there and I think I will put it back in and see if it makes any difference.

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I've never found that low of a stat to be worth using. I always use and suggest a 180 for a SBC no matter what part of the country. But I'm just an old phart so what do I know! Most newer Chevy's use a 190.

Rattler

Biggest advantage to running the T-stat is quicker warm ups!!

Good luck!!