Wanderlodge Owners Group

Wanderlodge Owners Group (https://www.wanderlodgeownersgroup.com/forums/index.php)
-   General (https://www.wanderlodgeownersgroup.com/forums/forumdisplay.php?f=19)
-   -   Do PT40s have any known overheating problems? (https://www.wanderlodgeownersgroup.com/forums/showthread.php?t=6750)

oldmansax 06-17-2010 08:02 PM

Do PT40s have any known overheating problems?
As some of you know, I am looking for an older PT40 to restore. Buy it cheap, and spend money later! :D:D

Do the early model PT40s ('80s models) have any built-in overheating problems? To clarify, I know if the system has been modified, problems can show up. What I want to know is, if the cooling system is still factory stock, and properly maintained, will the coach over heat on long grades out west?

For example, my model MCI's cooling system is just adequate if everything is right up to snuff. Any modifications or lack of maintenance usually won't cause problems here on the East Coast, but out West it will overheat. Later model MCIs solved that problem.

So, how are the PT40s? Is the cooling system OK as is? Or am I going to be looking at modifications (misters, bigger fan, etc.)? Will '82s overheat but '84s OK? All of the PTs overheat? None had any problems? They overheat but it's a simple problem to solve?



Bluebird Bob 06-17-2010 09:02 PM

Hi Tom,
Altho my rig is a PT36, the same applies.
We had the rad pulled to check for being plugged...no problem, just had it rodded out.
We came from Seattle and found that our temps stayed around 190 almost all the time.
No problem if hoses are checked or changed out.
Dash ac on most rigs doesn't work and suck 30 hp anyways, so most don't used them, or like me removed the compressor and saved the 40 lb weight.
We all have a fan overide switch on the dash and if the water temps start to go higher, we can manually turn on the fan.
A lot of the guys turn the switch on when approaching a mountain anyways.
The rads are big enough if the bird hasn't been modified.

sfedeli 06-17-2010 09:03 PM

Less problems with the 6V92 than the 8V's. IMHO (the key word is "humble") 475-500HP is about the limit of our cooling system's capability. If you got bigger injectors at some point, or the radiator is full of crud, overheating may be more of an issue. I've had our 6V out through the desert southwest in July and did not have any problems running around Vegas, the Grand Canyon or out through 29 Palms into California. Temps were normally around 110 F and the radiator stayed in the vicinity of 195-200 degrees.

ejallison1 06-17-2010 09:19 PM

Took my 85 PT 40 (6v92) out west. At 9000 feet in Wyoming she wanted to overheat-I figured it was lack of air-she was blowing black smoke. New rad just installed but unsure if the hydraulic fan was working properly. Just went slow till we were over the mountain pass. BTW I think I preferred that 6v92 to the 8V92-better mpg. Can't really tell a difference here in the midwest on the flats and haven't been out west in the 8V92 yet. IMHO

peteaeonix 06-18-2010 01:00 PM

Big issue with rear engine busses is pulling oily vapors from the engine through the radiator -- then dust sticks to the oily residue. The concrete-like material builds up and blocks the radiator. On my coach (with the S-60) you couldn't see from the outside because the charge air cooler was in front of the radiator and from the inside, the metal shroud around the fan and some other accessories made it very hard to inspect the radiator. The area swept by the fan appeared clear.

When I pulled out the radiator, it was found that all the area outside the fan area was completely blocked with the oily dirt. About 1/3 of the radiator area wasn't providing any cooling. After the core was replaced (with a more modern "staggered tube" design), the water temperature stayed at 180 and only went up to 190 on some of the heaviest and longest grades.

I made it a practice to steam clean the radiator each spring and pressure wash it a couple other times through the year. That kept the 'stuff' from building up and blocking the air flow.

SGallaty 06-18-2010 01:14 PM

My stock cooling system PT40 rocked hard from memphis to texas then from texas to ohio with the grades and declines in kentucky and the cooling system rarely ever went above 190 except when it was >100f outside and we were on a long uphill and even then it never got to be a problem.

as has been said - make sure there's good flow and that the radiator is clean, and if nothing is wrong the 6v92 has adequate cooling.

I haven't seen an oil cooler on my bus, but that's something I might consider.

GregOConnor 06-18-2010 01:53 PM

Some bus configs are known to run hot and have engineered faults but the 8v Wanderlodge is proven good. the buses are engineered to run at a given temp. Heat is a result of stress so this is a good operator sign of the limit to push. Members here re engineer the fans, pumps, t stats, and other cooling to not show the heat sign of stress. Overheating is a result of operator error or system failure. fix the failure and the resulting overheating sign will quiet down its warning cry. mask the heat sign of a system/operator failure by reengineereing and you lose the clue overheating proves.

My 8v92 was getting hot so I pulled the radiator and had it rodded. it was 90% plugged. hard part was finding a shop that wanted to rod. most shops want to replace the core. I was able to get it cleaned up for $700.

one unique thing about motorhomes over ;busses , ;dumptrucks and tractor pulling trailers is that motorhomes are always pulling at full weight, full stress. Commercial drivers use extra precautions when loaded down over running mt.

I dont use fan override on the 8v92 because there is no belt involved. If I had a 3208 I would pop on the fan at a lower r to keep it from kicking on when the 3208 r's are screaming at 2800. I can watch the reaction of the 8v cooling system and know that things are running ok or not . running up 5%+ grades I dont use dash ac so I can keep a reactive watch on the cooling temps.

oldmansax 06-18-2010 08:13 PM

Thanks for all the replies. I am glad Bluebird engineered things right! I have a very good radiator shop about 40 miles away. I will probably pull the radiator on whatever I buy & have it checked out.


peteaeonix 06-20-2010 01:38 PM


Originally Posted by oldmansax (Post 61553)
Thanks for all the replies. I am glad Bluebird engineered things right! I have a very good radiator shop about 40 miles away. I will probably pull the radiator on whatever I buy & have it checked out.


Keep in mind that if you pay to have the work done, that most of the cost of a "radiator job" is the R&R of the radiator (especially in the S-60 models). That's why I elected to have a new (more modern design) radiator core installed in my bus. After paying roughly $3000 for the R&R labor (California rates), another $800 (or so) for the radiator core seemed a reasonable choice. (The core I used as a replacement matched the design on city transit busses used in the Bay Area -- with its many hills, etc.)

As for the engineering question -- before I went to the radiator shop I was looking at ideas such as adding a water mist system to aid the cooling system. (These are commonly used on motor coaches on the LA-Las Vegas run across the desert.) However, after I had the radiator work done, there were no further cooling issues. I never had to pay much attention (other than ensuring that the coolant was topped up) to the cooling system. (My coach had a tendency to use a little coolant -- but we never found a leak.) Obviously, I dropped consideration of a misting system for my bird.

While I did replace the core with a new design, this is not so much "re-engineering" what BB did as simply updating the component with the latest design that was rated for the S-60 engine in my coach. The shop owner stated that the new core had, perhaps, 10% more cooling capacity than the OEM core -- but to me, that was simply insurance for extreme situations. I would think BB would have used the newer design, had it been available for the original build.

For those who care, the new radiator core had a "staggered tube" design. Instead of the oblong tubes, lined up in rows (6 or 7 as I recall), the new design had cylindrical (round) tubes offset in each row so that the next row of tubes was centered between the tubes in the row just before. The air coming through the radiator must zig-zag through the rows. Still, it seemed like there was actually more air space, so the air flow was improved vs. the OEM core. Work was done by Contra Costa Radiator http://www.contracostaradiator.com/ . The company is a contractor to several transit districts in the area, so is well experienced with working on heavy equipment radiators. To see a photo showing this general design, see http://aceradiator.com/core.htm

When climbing steep grades (remember, since we were home based in No. California, we regularly crossed the Sierras or Cascades to get out of town) the oil temperature would climb from 200-210 (normal) to 230. Although the manual said 250 was the red line, I'd pull over and cool down if the oil temp climbed above 230. It rarely happened -- on the grades heading south on I-5 out of Oregon on a hot afternoon and on I-70 climbing toward Aspen (above 10,000 feet where cooling air is kind of thin). Most of the time, the oil temp would rise to 230 -- and just 'hang' there -- so the cooling system managed to keep everything happy.

oldmansax 06-21-2010 07:43 AM

Thanks Pete! That's good info to have. I will pull the radiator myself on what ever I buy. I have the shop, knowledge, & tools. We have a heavy duty radiator shop about 60 miles away so I will probably take it to them & see what they say........ and make sure they include your suggestions in the fix.

Thanks! TOM

All times are GMT -4. The time now is 06:06 AM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.