Snowdoggie
Snowdoggie HalfDork
9/14/20 9:05 p.m.

I have a nice radiator leak on my 78 Dodge Motorhome and it looks like I have the original radiator. I am looking for an upgrade for it because it is big to begin with and I may start towing small trailers with it. Who makes heavy duty radiators for these beasts? It also needs a new fan. 

Any other way of improving the cooling system?

drock25too
drock25too GRM+ Memberand Reader
9/14/20 10:23 p.m.

Have you thought about an aluminum radiator and a good transmission cooler? 

Snowdoggie
Snowdoggie HalfDork
9/14/20 10:40 p.m.
drock25too said:

Have you thought about an aluminum radiator and a good transmission cooler? 

I had a bad experience with a Chinese made aluminum radiator in my XJ  Cherokee. Multiple leaks in less than a year. It was an expensive mistake. That has kind of turned me off to aftermarket aluminum radiators.

Purple Frog (Forum Supporter)
Purple Frog (Forum Supporter) GRM+ Memberand Reader
9/14/20 11:51 p.m.

If that old radiator worked fine for 42 years is there a need to change?  In my area there is still an old fashioned radiator shop that totally rebuilds the old ones.  Might be the easiest solution.

You can send the old one to custom aluminum radiator builders, and they will build one to match mounting hardware, etc.  And be more efficient.  $$  Companies like Griffin and C&R.  They even will custom fit the mounts for electric fans.

Adding separate oil and trany coolers takes some of the heat load off the standard cooling system.

My big gasser motorhome has electric fans to help the standard fan.  I'm now using a larger separate oil cooler mounted ahead of the stock radiator.

914Driver
914Driver MegaDork
9/15/20 6:47 a.m.

Find a local radiator repair shop, have the core replaced.  If it is a 3 row, get a 4 or just ask for advice.  Get the tranny cooler no matter what.

Ian F (Forum Supporter)
Ian F (Forum Supporter) MegaDork
9/15/20 6:53 a.m.

+2 for finding a radiator shop. 

Oddly enough, when I needed a new radiator for my Dodge Cummins, buying it from the radiator shop (they said plastic tank radiators are not cost-effective to re-core) was cheaper than Rock Auto.

I've read in a few places that brass radiators are more efficient (transfer heat better) than aluminum and the only reason to go with aluminum is when looking for weight reduction - something you would not noticeable in a motorhome.

Tom1200
Tom1200 Dork
9/15/20 11:05 a.m.

It's likely that radiator was from some truck application if, if you know what it was you can shop around for a bigger rad or as others have said you can just go to a local shop; if it's a 3 core you can go to 4 core.

On my E250 camper van I put a tranny cooler on it when I bought the van. On the radiator I went to a 4 core (from a 3 core), the van is 7180 plus I'm pulling 2400lb when it's 107 degrees out (gotta love the desert).   With the 3 core radiator the van was borderline on long grades.

Snowdoggie
Snowdoggie HalfDork
9/15/20 4:49 p.m.
Tom1200 said:

It's likely that radiator was from some truck application if, if you know what it was you can shop around for a bigger rad or as others have said you can just go to a local shop; if it's a 3 core you can go to 4 core.

On my E250 camper van I put a tranny cooler on it when I bought the van. On the radiator I went to a 4 core (from a 3 core), the van is 7180 plus I'm pulling 2400lb when it's 107 degrees out (gotta love the desert).   With the 3 core radiator the van was borderline on long grades.

The chassis is basically a Dodge B300 one ton van. 

frenchyd
frenchyd PowerDork
9/15/20 5:12 p.m.

In reply to Snowdoggie :

Air. The more air that flows through the radiator the cooler it will run. 
motirhomes are terrible about moving air through the engine compartment. Everybody wants the engine hump to be as small as possible. Too small means poor air flow. 
 

It's not about fans either. Fans obstruct air at high speed,  they do pull it through at stops and slow speed.  
So look to make sure that air cannot escape past the radiator. Seals in good shape,  no holes that are too big or no longer used?  License plate, fog lights, or plaques obstructing air flow?  Is the bottom of the radiator open?  Air will back up in front of radiator and if open pressure forcing air through  will go underneath so seal up everything, air that enters your grill must go through your radiator to give the best cooling. 
is the sound blanket falling down and obstructing air flow past the radiator?  Could you position hoses etc out of the way of good air flow?  
 

If the radiator is plugged then so is the engine block. Back flush until clean. Then forward flush until clean.   Pop a freeze plug and check your work. 

Tom1200
Tom1200 Dork
9/15/20 5:27 p.m.

Rockauto shows a 3 row radiator for a 78 B300 with a 440 engine, cost is $213.

 

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