Hello,

I have read many of the related topics on this forum trying to find a possible cause of my overheating E250. The van is a 1992 with a 351W. It is an "Okanagan" camper van (related to the Airstream B190). I've owned the van for ~6 months and these months have been cooler so this likely masked the cooling problem. Or it could be that the cooling problem recently started.

Yesterday on a warmer drive home from family camping I noticed the dash temp gauge up around the "A" in "NORMAL". This struck me as odd becasue I was used to seeing the needle straight up and between "R" and "M". At points during the trip the needle made it to "L". I was driving carefully (not a heavy foot) and ambient temps were 80F. I know these guages can not be counted on to provide accurate temp values so I bought an infared heat thermometer and ran some tests this evening. I did determine that the dash gauge is reading reasonable numbers.

I started the van and let it idle for ~20 minutes. Dash gauge settled right between "R" and "M". While it was warming up I was measuring the temp at the top/inlet rad hose and the lower/outlet rad hose (thermostat housing hard to reach to get a good reading). With the guage between "R" and "M" the inlet measured 197 and the outlet measured 172. Also, I am confident that I have either a 192 or 195 thermostat in this thing because the rad inlet was measuing ~90 until it suddenly jumped to ~195.

Now, when I get in and drive this van the needle slowly drifts up and down a lot depending on the driving. For example, if I am crusing with a light foot then needle sits around "M". If I am going up a decent hill for ~1min the needle will creep up a letter to "A" (and sometimes beyond). It seems to get hotter if the E40D shifts down to 3rd and RPMs go higher. I kept driving up and down the same hill and discovered that whether the A/C was on or not made no difference. I did notice that temps went higher with O/D off (maybe because of higher RPMs?). I stopped and checked temps at different dash gauge points and discovered the following mapping:
Top side of "M" is 208 at inlet and 198 at outlet. (delta = 10)
Lower side of "A" is 212 at inlet and 203 at outlet. (delta = 9)
Middle of "A" is 218 inlet and 209 outlet. (delta = 9)

What I found was that it was common to go from 195 before the climb (between "R" and "M") to 210 after the climb (top of "M"). Once I climb the hill and turn around I can get the temps to drop back down to 195 if I coast gently down the hill at a decent speed (between 50 and 60 mph).

If I climb the hill to get 210 then pull over and let van idle it takes about ~10min to drop the temps back down to 195.

I don't have many long/large hills around me and I wanted to see how high the temps would go if I could continue climbing. It seemed that higher RPMs increased the temp faster so I decided to replicate this with the following test. It was my final test because I scared myself too much to continue testing afterwards. I put the van in 2nd gear and drove a gentle hilly country road at 40mph. I did this for about 10 minutes and watched the temps go from 195 (between "R" and "M") up to middle of "L"! I stopped the van and got out to measure these temps and as I was about to measure temps I heard the overflow jug start to boil. Just as I heard this I saw the reading on my thermometer and it was reading 265F at the inlet. Holy frick, so I jump back in the van and see the gauge is now well into the "HOT" zone. I shut the van off immediately and the boiling stopped within 30 seconds. I kept the ignition on so I could read the dash gauge and when it dropped back below HOT after ~2 minutes I start the van again to get the fan moving. I felt like a dufus to allowing the temps to get so high but I swear I stopped the van when gauge read in the middle of "L" (and "L" is still in the "NORMAL" zone). Something happened when I stopped the van and jumped out to check temps. Something caused the temps to reach the point of no return and skyrocket. When I started the engine again the temps dropped down to ~200. Well, I can definitely say this test proved that my cooling system is inadequate in some way.

My drive home was very gentle through town with lots of stops and starts and a few gentle hills. Temps climbed up to ~225 just doing this slow cruise through town. So it seems like it's getting worse.

When I got home I asked my 12yo son to jump in the driver seat and rev the engine and I checked that the lower hose was not collapsing with higher RPMs. It is not.

So, I am looking for next steps please. I REALLY appreciate any recommendations. I am about to fire the parts cannon at this thing and just install a new rad/pump/thermostat/hoses/fan clutch.

-Curtis

 

It sounds like your radiator is plugged up, like mine was
Mine didn't seem plugged up during a flush and thermostat change
It was a troublesome diagnosis for me, as I was in denial about the radiators condition
Someone had put stop leak in it and it plugged up some of the bottom fins
I'd replace the thermostat first, and if still overheats, replace the radiator

 

Thanks! The following thread is another case where very similar symptoms were caused by clogged rad:https://www.ford-trucks.com/forums/1...placement.html
I jumped the gun and ordered a new rad this morning. I will get a thermostat too and test before installing. Plan will be to install new thermostat then test. Then install new rad and test.

I also forgot to mention that the coolant in this van looks brand new. Bright green colour. This hints to me that somebody might have flushed it recently…which could lead to a clogged rad.

Also the rad cap looks new and is 16psi.

 

Sweet
Let us know
I'd maybe reuse the coolant
I could break out my coolant tester I never use anymore and see if the coolant is any good
I'd probably just reuse it without testing it

 

Honestly sounds like you're on the right track with the radiator. That "looks clean but still overheats" situation always makes me a bit suspicious — like someone may have flushed it right before selling it

I'd probably start with thermostat + radiator as well before going deeper.

 

Thanks guys. Today is Thursday (May 21) and my thermostat is arriving on Monday (25) and new rad arrives next Friday (29). It will be easiest to do both at the same time so I will likely do this next weekend. Stay tuned for the verdict after next weekend.

In regards to the new-looking coolant: I bought this van from an older guy that only owned it for a year. He bought it from friends that owned it for many years (~10). It is a big ole' camper with a massive fiberglass dome on it...looks like a mushroom...it's actually quite rediculous. The old guy was planning to camp in it but he barely drove it (<300 miles) becasue he has a larger class C motorhome. I suspect that the long-term owners ("friends") did some fluid changes before handing it over to him. The trans fluid looks bright red so likely they did this too. If I was placing a bet, and if the problem ends up being a clogged rad, I would guess that they did a coolant flush then handed it over and this flush lead to the clogged rad. Who knows though. Also the rad cap is new and is a 16psi which is higher than factory spec (13psi)...so I have a hint that somebody knew something was off.

-Curtis

 

Since you already have a rad on the way, just for grins, you should partially drain the rad so the top of the tubes are exposed. Then you can see how much they're clogged.

 

Looking at your numbers, the cool-down difference of coolant flowing thru your radiator looks NORMAL. _ _ seems 15 to 20 degrees difference is optimum.
My wife's '07 Suburban 2500 runs normal at 210* and goes up to 255* on the long hard pulls climbing into the Sierra Nevada Mountains on a summer day of 100*.
Years back, on my Mopar 413 in our Class A Winnebago Chiefton 24-footer, there was one year the temps of the engine climbed slowly, then didn't go down. _ Hmm.
My suspicion was the Fan Clutch. There are 3-hard climbs and we had to pull over near the top of each, and let the coolant Belch and engine cool-down.
Once home, as I could investigate, _ _ the Thermal Strip winding was missing from the front of the Fan Clutch that engages it. _ _ what the heck !
I began feeling around for small rocks on the top of the Crossmember below and behind the radiator, _ _ and there lay that thermal spring coil.
I ordered a new Fan Clutch thru Napa after the salesman and I measured the diameter and pitch of the fan to determine which clutch we thought appropriate.

I've a friend with a Falcon powered by the 460 efi engine. It is a single-wheel in rear, Falcon, and he said it is so heavy it should have duals.

Here is another HEATING example:
My red Renegade with the AMC 304-V8 and stock 2-row radiator. This Renegade is a '77 Jeep CJ-7 which i've owned since '81.
I've kept it bone-stock engine wise, and early on, I had overheating issues and after the third tim I had the local Radiator-Guy rod it out, he said LAT TIME ! _ _ in around 1990 ?
This jeep was used to run the Rubicon Jeep Trail annually for 16-summers. I think early on, it blew a heater hose, maybe 1982-ish.
Could that have been from a submarine trek in the local creek a few times ?
Because when the jeep had to work each year, the most demanding of the Rubicon Esperience, was the drive overloaded from Pollock Pines on Hwy 50 above Placerville, Ca,, up the Ice House Road to get to the trailhead at Loon Lake, elev., guessing 6K feet. That engine overheated so often my brain is fuzzy.
Jump forward in time: - the last summer of the Rubicon was 2001. Done. That Renegade with a Borg Warner T-18 4-speed with a 6:1 Low never broke.
Most breaks on that trail are due mostly to OPERATOR-ERROR / DESPERATE DETERMINATION. _ _ i've witness both. _ _ usually inclusive. _ LoL
The Renegade got put into moth ***** in 2001 until early year 2022. I fired it up and it ran terrible. Upon shaking loose a few gremlins, I got this brain-fart to invite my oldest daughter to join me as a father / daughter team to attend a weekend Jeep gathering basecamp Upper Lake, California. _ _ i'm getting to the POINT _ _ _
The day we departed Anderson, California, it was 104-degrees out. We blew down the valley interstate 5 headed south and west 155-mi. to basecamp, Upper Lake.
All went well until we entered into the coastal mountains and the climbs to get over the four passes. Well, wouldn't ya know, that was where my luck ran out.
I was careful in my prep for the trek weekend, and because my dash analog temp gauge wasn't working, I bench tested in the kitchen with wife's candy thermometer, an New cheapo electric temp gauge with sender. The gauge temp readings agreed with the candy thermometer, so I knew real numbers.
Up we went climbing the first long-a** grade and about a third of the way up, the gauge was reading 220. No biggie, continue on for not much further, and when the temp hit 230, the temp quickly jumped to 240, and I pulled over. The coolant had belched everywhere all over the engine. I had constructed a nice Over-Flow canister with a snap-top.
We dealt with the overheating thru the weekend,and when I got home and was cleaning the engine, _ _ _ I spotted a lower head bolt with the HEAD MISSING !!!
I welded nuts to the end of the bolt and a breaker bar would just twist the nuts off. Third nut, I gently tapped the nut with my Snap On 1/2" cordless impact wrench each way several times and it broke loose.
I got a "new-used" oem head bolt and torqued it to near spec and my cooling system if working super nice and temps are behaving.
I removed the Over-Flow cannister too, now that the system is stabilized.

Out of curiosity, once you remove your old radiator, turn it upside down and give it a good flushing.
My radiator guy told me he has chemicals he uses to soak the inside overnight before flushing. _ _ he knows radiators.
Before I found the broken head bolt, I had him check the engine and radiator temps like you did, and he said my radiator was working fine. _ I had him rod it anyways.

 

Thanks for the stories, fun to read! Think that head bolt was missing its head from the first time you experienced overheating in the renegade decades before?

I went for a little cruise last night when outside temps were 50f. Coolant temps never got above between R and M (I estimate about 195). I never pushed too hard but with the same driving at ambient 80f the coolant temps would definitely have climbed.

I also now think the thermostat is 180 after another idle test where I measured the rad inlet as the thermostat opening. It started around 180, not 195. I will know for sure when I remove the old thermostat next weekend.

During the same idle test I noticed a much higher delta across the rad. With 195 on top inlet the bottom outlet measured 140ish. I also noticed the center of the bottom tank might be a bit colder than the outsides at the bottom…by about 10f. Might indicate clogging in the center passages. So this 55f delta seems high and indicates coolant spending lots of time in the rad.

when I remove the old rad I will definitely peek inside. I was also thinking about taking a zip cut to the top tank and cutting it all off to see all the passages. You know, for science (or “grins”). Or do you think it is smart to get the rad rodded as a spare?

 

If you have a copper radiator, get it repaired or recored, parts stores will give you one with a plastic tank, mine was copper, the brackets came off and it started leaking, shop put a 4 row aluminum racing radiator in it, recently, after a new engine and everything under the hood replaced, doing a burnout the fan destroyed that aluminum radiator, now it has a plastic tank replacement. Mechanic is puzzled how the fan decorated the radiator, we all know the van is cursed, so nothing is a shock anymore, they call it Christine, and I never told them to plastic clip, retainer for the prop rod came out, slamming the hood on my hand one day, just like in the movie, never trust the hood prop if it has the white plastic holding it in the hole.
BTW the green coolant is only good for 3 years, any coolant will pick up acids from combustion so they don't last forever, if you have buildup, beware flushing could cause the heater core to get damaged.

 

I bought a straight aluminum one for my 94 with a 5.8 off Ebay for cheap and love it
Brass one I scrapped with my aluminum and steel was fun
I think I got the 4 core one and it is a bit of overkill
I do have sufficient heat in UT but barely
Truck now loves the west desert 117 in the shade and never goes over half on the factory idiot gauge

 

I would paint the very front of it black if I had it to do over again
The area right behind the grill would look better black
I can get one for 126 bucks from 1800 Radiator, but they are cheap like Maples says
Hell, the aluminum ones will not last forever either, but mine has been in there since 05
I do keep clean new coolant in it

 

I bought one for my 99 E350 from Ebay, was still functioning top notch 15 years later when I sold it, don't know how the 89 E150 was able to put a pretty circle in the one put in it by the fan, it wasn't that close, Ebay had another aluminum one cheaper than what dad paid for the plastic junk. The cores on the aluminum radiators are so much bigger than the copper ones, they can move so much more coolant a 2 row is better than copper 4 row. I also did the fan clutch in the 99, and good thing too, when it was off, you could see it wasn't working, and on startup you could hear the difference, feel air blowing out the fender by the drivers door.