I have a 1990 Winnebago Warrior that started overheating on a 1300 mile trip a month ago.
Initially, we had noticed at one point in the trip that the temperature rapidly spiked and dropped, so I suspected the thermostat.
In draining the fluid for the thermostat change-out, I looked down the filler neck of the radiator and noticed that there was a lot of encrusted deposits around and intruding into most of the radiator cores. So, my suspicion is that the 28-year-old radiator is full of mineral deposits. I have, in the past, topped up with regular tap water, which I now understand is really bad. It's like the "exercise your generator" advice - it really is important to use distilled water in your cooling system and you can buy it at Walmart or any grocery store. Here you can see the deposits:
When I finally pulled the radiator and was able to look inside through the outlet connection, the deposits were even worse on the bottom end of the radiator.
Anyway. I decided to repair or replace the radiator. Now the stock OEM radiator is brass/copper construction, with 4 rows of cooling tubes. I found an "exact fit" replacement from Advance Auto Parts for about $230 (with 25% discount - if you put something in your shopping cart and leave it for 24 hours you will get a prompting email with a 25% discount code).
However, this "exact fit" replacement, while also of brass/copper construction is only a 3-row radiator. Now I have not received it yet, so I have not looked inside it, but I'm betting it does not have longer rows, just fewer, which means it will have less cooling capability than the OEM radiator.
In addition, my unit has a tee-off from the outlet bypass hose coming out of the intake manifold. This tee-off runs down to a restricted orifice in the bottom of the radiator called, I believe, a "sensor port". I have read that purpose of this bypass circuit is so that there is coolant running through the radiator, down by the transmission cooling circuit, on engine startup before the thermostat opens up to aid in warming the transmission and getting it up to operating temperature quicker. I suspect that this circuit is probably not necessary in Alabama but I wanted to put it back in stock configuration. Unfortunately, the Advance Auto radiator does not have the sensor port. So that is 2 strikes against it.
Here is the tee-off:
Here is where it connects on the radiator:
Here is the Advance radiator: https://shop.advanceautoparts.com/p/carquest-radiator-432195/15920038-P
So, after having a long discussion over on this forum:
https://www.ford-trucks.com/forums/1543596-suggest-a-radiator.html
Some helpful folks helped me locate this radiator:
https://www.carid.com/liland-global/radiator-mpn-1291aa3r.html
Be aware that when you try and buy this through their shopping cart the price is like $237, which is awesome, but they try and hit you with $212 in shipping fees. But they price match, and when I chatted online with them and told them I found the same radiator from another vendor for $312 with free shipping, they gave me a $199 discount so I got the radiator for like $257 shipped, which is only $30 more than the 3-row Advance Auto radiator.
This radiator is all aluminum. They say that aluminum radiators are more efficient than copper/brass ones. Something about brass being a better thermal conductor, but the solder that is used to hold the core together is not so conductive. But the aluminum radiators are held together in such a way that greatly increases the thermal transfer capabilities. Also aluminum radiators are much lighter. There are issues with galvanic and electrolytic corrosion you have to worry about with aluminum radiators. This is mostly solved by having a very good engine ground or electrically isolating the radiator.
This radiator also has the needed "sensor port".
Anyway, my point in all of this is that the aftermarket radiator you have installed, while being an "exact fit" for you E-350 with 460 engine, may not be engineered well enough to handle the thermal demands of an RV with only 2 rows.
Picking an aftermarket radiator for these older RVs is tricky since it's hard or impossible to get an exact OEM match. I'm rolling the dice with the Liland radiator I have settled on and I hope it is up to the task.
If you have replaced the thermostat and the radiator, and you don't have a head gasket leak (they can put a "sniffer" in your filler spout to sniff for exhaust gasses, or you can look for bubbles in the coolant - never open while hot though), then you should not be overheating.
My suspicion is that your radiator is not up to the task.
The Spectra is listed as a "2 row" radiator and I don't know what that means.
If you remove the filler cap (when cold) and look down in there with a flashlight, you should be able to make out the tops of the little tubes that run top to bottom in your radiator. Those are arranged in rows. The number of rows tells you how many rows you have. A 2-row radiator will have 2 rows of tubes. My OEM radiator in my 1990 E350 had 4 rows. The "exact fit" from Advance Auto has only 3 rows. They claim that it replaces the 4-row radiator, but I am skeptical. Which is why I went with the aluminum radiator.
When using a laser temp what should operating temps be? Where should I point the laser? Should the upper hose be the same temp as the lower hose?
Point it at the upper hose. Should be 200F-215F I would think, though I don't know the exact operating temperature for our setups. The lower hose should be much cooler since the coolant goes in at the top and comes out at the bottom and returns to the water pump. If the radiator is cooling at all the bottom hose should be cooler than the top hose.
Steve
