Prevost and 8v92 question

Ace · January 05, 2013, 06:27:25 PM

How many Prevost owners with 8v92 know if they have an "engine guard/air deflector" still in their bus?
Most mechanics to my understanding remove this piece if they ever do any transmission work.
If your finding your coolant temps rising as your mph climbs, this COULD be the reason!
Mine was removed sometime before my ownership and I had no clue it even existed!
Since Prevost no longer stocks this item, I am left to fabricate my own. Not a hard chore but very dirty and time consuming!
If you choose to make your own I would suggest using mud flap material! A plastic type works better than rubber and once your into it, you will know why!
Mine hopefully will be completed tomorrow and then a test run on the interstate! Hope its hot out!

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Utahclaimjumper · January 05, 2013, 07:29:00 PM

Bring it up here Ace,, its up to 10 below now.>>>Dan

rip · January 06, 2013, 10:47:30 AM

I have a 85 Prevost and mine apparently does not have one.I have never seen one before,could you take a photo of the one you made? Don

Ace · January 06, 2013, 02:46:19 PM

Okay I just finished the fabrication and installation of said air deflector and engine guard but not a good day to test drive! Overcast and drizzly! Time will tell if it helps or not but the experienced owner/mechanics I talked to in Arcadia swear by it! Besides, I never knew it was on to begin with but it DOES make sense!
I will post pics soon!

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bobofthenorth · January 06, 2013, 03:19:45 PM

I don't have one but I was thinking maybe it would keep snow from flying up onto the towed. We're up to a balmy -7C today - no worries about overheating for a few months.

Ace · January 06, 2013, 04:07:34 PM

Here are some pictures of what I'm talking about!
Its not mounted on or under the rear bumper or under the motor.
It wraps the transmission way before the engine compartment!

Prevost diagram

Right side looking towards rear from in front of transmission while under the bus!

Left side looking towards rear from in front of transmission while under the bus

This also goes up to the bottom of the floor area and to my understanding it reduces the air pressure that is created without it in the entire engine compartment and thus allowing the fan to draw in fresh air thru the radiator easier! Without it, a higher pressure is evident in the engine compartment forcing less air to flow thru radiator. With it, the air is deflected downward and exiting under the bus and outward exiting to the sides resulting in less pressure in the engine compartment!
I feel if it's good for 5 degrees or 5 mph, its time well spent!
Total cost about 100 bucks! The mud flaps were 20 bucks each but any good plastic or rubber would work!

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robertglines1 · January 06, 2013, 04:49:57 PM

The 89 XL has one and never had overheating problems FWIW. Was soft enough you could squeeze your arm thru but laid tight. Never new function until now for sure but makes sense. Thought it was to keep road dirt etc out of engine area. Never thought about air flow effects. Bob

Ace · January 06, 2013, 06:04:16 PM

Bob, to my understanding most all 8v92 and even some 6v92 and 8v71 Prevost came with it installed but were a nuisance whenever any trans work was done so the shops leave them off thinking they are only a stone guard!
I'm really anxious to see if there is an actual difference in higher speed temperatures as I'm told to expect!
It gets old when you can only go 65-70 mph and see the temps rising to 190, 195, and going up the faster you go!

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bobofthenorth · January 06, 2013, 06:32:59 PM

I'll look forward to your report Ace. It makes perfectly good sense and it sounds like a good weekend project. Not that I'm really short of projects ... but it sounds like a perfectly good weekend project.

PP · January 07, 2013, 07:35:17 PM

Mine is still on but i thought it was called an air-dam. The first time I mentioned it to someone, the person thought I was cussing because they didn't have a clue what I was talking about.

chessie4905 · January 08, 2013, 05:19:25 PM

I had the same problem while at Hoover Dam with the damn guide on the damn tour. We were told to stay with the damn group and not to wander into the damn tunnels.

Oregonconversion · January 08, 2013, 11:38:24 PM

When I got my MCI with 8V92 they were off and in the bay. I keep them just incase I want to put them back on some day.

PP · January 10, 2013, 06:16:00 PM

Quote from: Oregonconversion on January 08, 2013, 11:38:24 PM
When I got my MCI with 8V92 they were off and in the bay. I keep them just incase I want to put them back on some day.

Which dam bay were they in?

Too easy, couldn't resist, Will

Oregonconversion · January 12, 2013, 04:56:46 AM

The one where the watermelons grow.

tomhamrick · January 13, 2013, 05:09:44 AM

Hi Ace,

I am in the process of replacing my air bags and this piece is still intact on my 91 H3. If the bus would run hotter without it I sure am glad I have it!! I just replaced the radiator and thermostats and still run at 195 degrees on the interstate. Pulling a mountain in 100 degree weather it will get just over 200 even trying to slow down. That is probably not bad but I am glad I have the orginal air dam.