Engine temperature

[Fratto]

My thoughts exactly. The load would be inconsequential to a 500 hp engine.

[Joe Camper]

When you've got OTR A/C the condenser is over in a bay on the other side of the bus. With Dash air only the condensers there by the radiator and the radiator catches all the hot air coming off the condenser.

[Fratto]

Agreed... but do we think that the condenser temperature is enough to raise the engine temp 10 degrees or more? It doesn't seem like there could be that much thermal energy compared to what the engine is already delivering to the radiator.

[Joe Camper]

I think it will. I chauffeured a barrel Rider who had a Liberty with over-the-road AC through Texas and Oklahoma a few Summers back it was a very hot summer. We were pulling a trailer with a horse in it and that poor bus was north of 210 ALL SUMMER LONG, had me real nervous all the time I hated it. I had that gauge burned into my brain I looked at it so much. If u would walk back there during short stops idling, heat was radiating off the engine room like it was a nuclear reactor. It never shut down or overheated not even once. That's where it ran.

My Prevo had over the road AC too. It was an 8v but it would run between 10 degrees+ hotter when I had the over-the-road AC going. 180 without 195 with ac on.

It's not really a good comparison to make with a non over the road AC bus but I think the same scenario applies even more so with yours cuz where the condenser is.

The over-the-road AC chassis pick up additional heat off the additional load of turning that gargantuan 6 cylinder AC compressor and on the non over-the-road AC coaches the extra heat gets picked up off the condenser.

I'm not sure what year coach you've got but the early 60 series coaches lacked a bunch of louvers above the engine bay doors that they inserted in latter years that cooled the engines down better.

I think also possibly once it gets North of 95 degrees or so all things change. If it were a more moderate air temperature the fact that the fan gets turned on high speed will get it cooler and it should, but, when it gets north of 95 outside all bets r off, the temperature goes up not down.

I never never never run in the heat of the day when its north of 95 and my current powerplant is a mechanical cat that never gets north of 190. Still won't do it, I'll go at night when it is and I have to get somewhere.

Mark I see you're from Arlington Texas. I'm currently doing some work on a Liberty in Lufkin and I'm going to be in Boyd with a CC the end of the week, that's just a little west of Fort Worth. Be there all weekend maybe longer.

[Fratto]

Thanks Joe. We have family in town this weekend or I would drive out and say Hi! Good luck on the CC.

[Gil_J]

I've never seen or heard of the engine temperature increasing with Prevost's Dash Air on. In fact, most note lower temperatures given on most model years the fan clutch is engaged in the high speed setting with the air on.

[Loc]

Without the dash air off we will cycle up to 210 and then drop back down to 190 and then start all over again. With the dash air on (fan locked in) we rarely get above 205 unless we are pulling hills and most of the time are in the 185 to 195 range.

[Joe Camper]

I still think once u get north of 95 outside things change.

Next time someone is out in 95°+ with a dash air only chassis we need to know how it does.