Thanks to you all for your inputs. I was well-armed with my discussion with the dealer yesterday. Aside from my service manager, they had their lead technician there (27 years experience). I think the issue was a mistranslation by the service manager. The radiator was replaced with a new, metal one, new thermostat, coolant flush, heavy duty fan and clutch, and transmission flush and adjustment within the last two weeks. Top of engine was rebuilt about 10,000 miles ago.

The Roadtrek modification is heavy--oak panels, holding tanks, propane, etc. Likely weighs very close to 7700 lbs all the time. Brought the van home and changed my driving habits a bit. Coming up the long hill (gaining 2000' feet in about 10 miles), I turned the overdrive off at the start and left it off. Engine temp was about 170 at the start and 200 at the top. Going up the larger grade (about 800' in 2 miles), with the air conditioner running, overdrive off, outside temp 60 degrees, and pedal depressed about 1.5", reached bottom of hill about 30mph and top of hill at 50mph. Engine temp about 225. Engine cooled down to 170 by the time I reached home. The engine stayed in second climbing the hill and that seemed to make it happier.

I think, thanks to your help, that I now understand the vehicle better and can change my behavior. The other day when it got real hot, I wanted to see what happened if I left the overdrive off on the long climb--and that contributed to the problem. Now, if it is really hot, I'm just going to pull over at the bottom of th steeper grade, turn off the air conditioner, and run the car at ~1500RPM until cool.

I also plan on selling the vehicle in about six months--to my service advisor!!

Thanks to all!

 

I'm not sure about your trans model but on mine the transmission fluid does not circulate when in park. When you pull over, you may want to keep it in neutral with the parking brake on and your foot on the brake so your trans can cool down.

 

Wow! I didn't know that!

 

I confirmed that the fan clutch was replaced when the fan was replaced. The other day, at 85 degrees, I had to pull over twice for twenty minutes each time to allow the vehicle to cool down. A short summary:
- the radiator was replaced (twice)
- the coolant system was flushed
- the fan and fan clutch were replaced
- the thermostat was replaced
- issue began after the transmission received normal flushing service

The vehicle is operating in the same environment it has been for 10+ years and 90,000+ miles. Something is different. Now accepting wild and crazy ideas. Last idea received: maybe the coolant mix is 100% coolant instead of 50/50. Suggestion: replace all coolant with water (just for the test) as water can dissipate heat faster.

My plan is to document all the work done by time and mileage and take the vehicle to some old crusty guy who has been doing this for 30 years.

 

Have you done a compression test to look for a blown head gasket?

 

CWdO4l

Alloro may be on to something, it is safe to say you have ruled out the cooling system (of normal problems). I was wondering if you have the 5.2 as I recall folks have mentioned 5.2s running a bit warm when pulling trailers up hills. Conversion vans seem to be affected the most, this happens to be the first time I have read about running warm unladen with a working cooling system. Have you considered a possible internal problem?

 

I will suggest the compression test when I take it in next week. Thanks.

 

I'm still accumulating repair history, but I finally nailed down the elevation change over distance and calculated grade by segment. Just wanting to share. Numbers are:
Segment #, Distance (miles), elevation change (feet), Grade (%)
1, 2.0, 409', 3.9%
2, 1.7, 439', 4.9%
3, 0.9, 316', 6.6%
4, 0.5, 108', 4.1%
5, 1.2, 506', 8.0%
6, 1.1, 167', 2.9%
7, 2.2, 63', 0.5%

 

The place to begin is always with what was done last. These transmissions require ATF+4. Not dexron + an additive, despite claims to the contrary, no other fluid will work. Did you change the transmission fluid yourself? The dealer should have known enough to add the correct fluid, but.. well, to put it gently, not everybody follows proper procedures.

I agree with checking to make sure the coolant is 50/50. Water actually cools 2x better than ethylene or proplyene glycol, we only add it because it has a slightly higher boiling point, lower freezing point and slows corrosion to a point. If you decide to dump some coolant and add water, use distilled water only.

 

Not to jump on nibroc here, but based on my recent experience an upgraded radiator should not not necessary.

I just pulled a 4600lb trailer with my 5400lb 5.2L Regency conversion van through the hills of Tennessee and Kentucky at 55mph in heavy traffic with no overheating issues whatsoever. A/C running the entire time, standard dual core copper/brass radiator installed two years ago, electric fan conversion. Of course, copper does transfer heat about 2x better than aluminum..

http://www.hotrodhotline.com/md/html..._vs_copper.php