radiator replacement

[Diesel Phil]

Hi! Airstream people. We have a 36' Airstream Classic diesel pusher with 5.9 Cummins engine and 6 speed Allison transmission with front mounted external transmission oil cooler. First, this intallation could use more cooling. Second, I am seeing green stains in the radiator and I feel it is time for replacement. Does anyone have any sources for radiators and what are your thoughts on aluminum custom radiators? I realize there are not many of these around but I know the A/S with 454's benefit from more cooling. I would like to hear about your experiance. Thank you for your replies, in advance. Regards; Phil and Sam

[overlander63]

Has the engine ever run hotter than normal? If not, I would say just replace-in-kind. If you have noticed it heating up, then an upgrade may be a good idea.
How many rows of cooling tubes does your current radiator have? If you have 3, you can go with 4, without changing much in the overall dimensions of the radiator (thicker core= more cooling capacity).

[HowieE]

The stains sound like you already have a leak.

There is no reason not to just have the radiator cleaned, roded, and repaired. Far less expensive than a new one. I thinks you will find a cleaned and pressurized radiator will solve the problem.

If you really want additional cooling see if your end caps will support an additional pass and have it re cored to the large size.

[GlenCoombe]

high performance rads can be had at Jegs or at Summit Racing.

If you're going to remove the rad for repair why not replace it with something that works better?

Heat is the enemy.

[Diesel Phil]

Hi guys! Thank you for your suggestions and ideas. Yes, I have seen it get hot. In fact, I discovered it had a coollant hot light...when it came on while driving along Lake Roosevelt in Arizona last July. Temp was 114' F. The good news was when I pulled off the road and ran at a high idle, it returned to normal, quickly. I don't think the pusher configuration cools as well as it should, especially now that it is making a little more power.
I don't know how many rows it has or who made it...I can't find a tag. I guess I need to find a radiator shop that knows what they are doing. It appears to me that the last overhaul was done with a can of black paint! Anyway, Thanks for your help. Sometime between now and Spring I will try to find the time to pull the radiator and figure out if it is rebuildable.
Yes, I agree. "Heat is the enemy!" As we are always in a hurry in the summer to beat our fire-crew to the next job! (and we ALWAYS do!) Those poor guys live in their little tents and WE sleep in our Airstream! Regards; Phil and Sam in Newport, Oregon

[crispyboy]

If their wasn't a cooling issue before hand I would just have this one rodded, boiled out and pressure checked by good radiator shop. While it is out have the thermostat replaced, check the condition of the hoses. If their is a fan clutch I would think about replacing that too.
I put an aluminum cross flow radiator in my tow vehicle and it made a lot of difference in the cooling ability. The temperature did not fluctuate more than 5 degrees this past summer. I have been thoroughly impressed but they are spendy.....

[ROBERTSUNRUS]

Hi, if this applies to your motorhome; Some diesel pushers have a fan that blows out through the radiator from the inside and they get oil from the engine on the inside of the radiator and it collects dirt thus clogging the air flow past the cooling fins and tubes. Since this happens on the inside of the radiator, it isn't readily noticed. A stock radiator should work fine if your vehicle has not been modified.

[Diesel Phil]

Hi all, Just got off the phone W/ Tyler @Spartan 1 800 543 4277.He tells me they have 6 rads. in stock @ 1189.15 ea.They are McCord p/n 0507 f1 Need to get the old one out & see if its rebuildable. Robert, Thats exactly what I want to do get rad. out & check out all things cooling .I dont think cooling fan clutch is working properly . Thermostat ??? Who knows whats in there??While I can get at it ,can install 200 amp altenator that I have been putting off for the last year. Thanks for your help.Phil & Sam

[HowieE]

As long as you are in there remove the thermostat and test it. Put it in a can of water and put the can on the stove. If the stat does not open before you see small bubbles forming around the edge of the can it may be bad. If it is not fully open by the time the water is boiling it is bad.

The clutch fan is hard to check. The best check would be before you remove the radiator go for a ride and watch the temperature gauge. If you don't hear the fan kick in before you see abnormal temperatures I would consider the fan as bad. With the engine in the rear you may have to have someone ride back there with a window open to hear the fan kick in.

Unless there is a bullet hole through the radiator you can have it rebuilt for a lot less than $1100.00 bucks.

On my trucks, which are easier to get to, I remove the radiator for cleaning or pressure wash the out side every couple of years. The newer fin designs, a venturi design, trap far more bugs than the older straight fin types

[Diesel Phil]

Howie,The fan starts turning as soon as engine starts .Is this normal ?

[HowieE]

A clutch fan is oil filled and will turn when the engine is running just from the viscosity of the oil. It doesn't turn at high speed while the oil is below the set point because the fan blade load retards the speed. If the temperature goes above the set point, and this can be as much as a 30 degree range from 170 to 200, there is a locking clutch inside the fan. Once locked the speed kicks up to a point that you can hear the fan turning.

The problem with these clutches is the wide range of activation. I was very lucky to have one on my Suburban that locked at a coolant temperature of 180 degrees and the truck never even approached high temperature. Other may not lock until 200+.

The important factor in causing the clutch fan to come on is to have a clean radiator, inside and out, to pass heat directly to the fan clutch. If there is poor air flow through the radiator or poor water flow through it less heat will cross the fan clutch and it may never come on even though you are overheating the engine.

[bkahler]

Originally Posted by HowieE

The important factor in causing the clutch fan to come on is to have a clean radiator, inside and out, to pass heat directly to the fan clutch. If there is poor air flow through the radiator or poor water flow through it less heat will cross the fan clutch and it may never come on even though you are overheating the engine.

Howie,

That's the best explanation I've heard for why a clutch fan won't work even after being replaced. Good reason to ensure a radiator stays clean.

Thanks!

Brad