Gettin' hot

[jdurham]

I just got back from a major road trip (for me anyway) I went from Al to Tx and back. Coming back I was towing an 18' open trailer with a 92 W250 w/ everything except the motor. You can see my sig on the mods done to my truck, and it is the stock 3 speed auto, non-intercooled, 3:07 geared truck. I was doing a consistant 70-80mph, and the temp would climb up to the top of the normal scale, a few times climbed over the normal band, and even once got just below the hot mark :--)



I read the post Dan Brooks put in where porting and/or a new turbo was recommended. I have an intercooler, core support, and radiator out of a 92/3 truck that I can put on my 90, but since Dan's truck already has these items, am I still going to run hot if I put these on mine?



As a side note, the truck had the oil light on at idle when it got warm, is that normal, or do I need to replace the oil pump?



Thanks,



Jim

 

[Case500D]

JD,



Not sure about the heat issue, but it sounds like the oil light at an idle is just a sending unit issue, not a true low oil pressure problem. I would stick a regular gauge on to confirm this. I know of a couple of non-intercooled trucks that have had this problem. Hope this helps.



Jeremy

 

[BushWakr - RIP]

I agree with Jeremy, replace the sender and also check your idle... if it is too low and you have any accessories on the idle drops even further and you can be too low for good oil pressure.

I have found that when in neutral an idle of roughly 800 - 825 RPM is just about perfect... if it were an auto truck I go as high as 850 - 875 RPM



As for the overheating I would suspect the thermostat right off the top...

Do you have any other symptoms to throw in... does the truck run cool when unloaded... on the highway... . stop and go traffic????





pastor bob...

 

[jdurham]

OK guys, thanks for the tips. I'll get a sending unit and maybe that'll be the only problem.



Bush, as far as the temp, it's fine except for loaded.

 

[Philip]

Hi JD



A thermostat would be my first try at the overheat. But most likely the raditor with its age is getting some cores stoped up. There are three ways you could check this problem.



#1 would be pull the raditor and have it cleaned and check for flow at a raditor shop.



#2 Find some infared 35MM slr film and go for a hard drive and take some pic's of the core and then have it devolped to see if it shows a even heat flow across and down the raditor.



#3 would be find a infared camera and do the drive test and look to see the heat flow across and down the raditor.



Time to set and think which way you want to attack the problem.

 

[jdurham]

Hi Philip,



I think the radiator is ok, had it checked not too long ago. Do you think the cross flow radiator like yours is that much better than the down flow I've got?



Also, after my mods, I never bumped up the timing, would that help?

 

[Philip]

You had it checked. But what did they check. Just for leaks or did they have a flow bench to see how much it would flow then check it against new spec's? Did they rod it out?



The cross flow is a better design. Most of the problem with the old top load raditors was the surface area is about a third smaller than a cross flow. The tubes in a cross flow are bigger most of the time. Plus that extra capacity helps to.



Not sure on the timing. Mine is still stock. The pump wouldn't move after I bought the snapon wrench to fit it. LOL

 

[bgilbert]

JD, I don't think turbo or timing will help with overheating or running hot issues. Time for the bigger RADIATOR. Hows the fan clutch, fan shroud, t-stat? My 89 doesn't run warm, has a good shroud, new MOPAR fan clutch, cummins updated t-stat, good antifreeze concentration and 5 speed OD transmission. The 91 runs HOT same as your condition, has a good shroud, decent fan clutch, don't know about the t-stat, good coolant%, I think the non-OD transmission has something to do with it, running 75+ is almost against the governor which is pushing the engine hard- high rpms combined with small radiator the engines just runs warmer than a OD truck and or one with a bigger radiator. I'd like to hear what a bad t-stat does to overheating/running hot issues! BTW my 91 runs warm empty when I'm running 75-80 for a period of time say an hour.

 

[michigandon]

JD, I don't think turbo or timing will help with overheating or running hot issues. Time for the bigger RADIATOR.

May I recommend:



http://www.streetrodstuff.com/Products/157/



I'm running a 28"x19" that they custom built for me with a '93 D250 drivetrain in a 12,000lb class A motorhome. Updated thermostat, Fleetrite 50/50 extended life coolant and a 3300CFM Zirgo electric fan. As long as the vehicle is in motion... even if its only 10MPH... the coolant temp never goes over 180*. The fan is set to come on at 200*, but it will only get that hot if stopped in traffic for more than 10 minutes.