MC9 Blues

[Seville]

You guys are great!
I was just about ready to pull the trigger on the engine transplant. Thanks to the good advice from all of you, Im gonna pass on that.
Boomer, your right about the MC9 radiators. Being as old as they are, its a small miracle they even work at all !

Buying one at a time is a good idea to ease the pain on the wallet.

After all, there are still many things I want to do on the actual conversion.

On a side note, I can't wait for the day when its 90 + degrees out and Im looking at some 2 or 3 mile climb and I know my temp gauge will stay at a nice cool 180 degree level.
I don't care if I'm doing 20 mph! As long as my temps are good, I will be a happy camper literally!!

[Lin]

Aside from all the other maintenance items mentioned, it may be a good idea to buy some condenser cleaner and clean the radiators so that you get the max out of what you have.  I think the sprays are about $5. at Home Depot.

[Jerry32]

I had a bus mechanic tell me pretty much all of them will over heat. I have never had a problem even running mountains in 100+ weather so I guess I am lucky with this 8V92   Jerry

[buswarrior]

ok, cheap fix time.

The MC9 does not suffer as badly from the "MCI overheat" as earlier models. If an MC9 with a 6V92 is overheating, it needs MAINTENANCE, and then it will be fine.

Inspect the radiators closely, inside and outside both sides. I expect you may find the fins rotting off a big area of them. After that, look for any gaps or wind tunnels in inspecting the SEALED CAVITY that should be the fan compartment. The ONLY place absolutely any air should be able to get into the fan compartment is THROUGH the radiator fins, and as small a gap where the fan belt goes through to the fans. There should be a chunk of rubber helping block that hole as best as possible without rubbing and making a stink.

Ignore any small gaps at your peril..

As noted, get a couple cans of expanding foam from the building supply store, and completely seal up the spaces around the perimeter of each radiator. The existing rubber bits will help make a form, just spray it in there, do it twice if you have to to be SURE absolutely no air will get around the rads.

Now, the radiator access doors on the back to either side need something down the vertical to seal air from flowing around the inside of the doors, a combination of inexpensive stick on weather stripping and some more of the foam. Those doors should be HARD to close against your sealing efforts, and have good contact their entire height with your sealing material.

Then we have the trouble of the fan compartment door. How are the seals? If you want to quickly rule them out for temporary purposes, while at the building supply, also get a roll of duct tape in the colour you would like to use on the rear of the coach. Tape all the fan door seals, right out beyond the position of the radiators, and the whole way around. It will take three passes, one over the gap, and then one above and one below to keep it stuck on.

Before all this, did you carefully wash EVERY SINGLE FIN, of both squirrel cage fans? Old toothbrush or similar tool comes in handy. Get comfortable, and mark where you started, this will take a while.

Also, are there any damper doors left in the fan outlet? They must be absolutely FULLY retracted. If they hang by as much as an inch, it can obstruct sufficiently to overheat. For the purposes of this test, disconnect them. I pulled the pins in the clevis on the actuator and left them hanging for now, I maintain my shutters for up here in the Frozen North. As noted earlier, these actuators are another source of air leaks, and for a busnut, little value for the time to spend rejuvenating them.

Get this lapsed maintenance caught up and carry on enjoying the coach.

happy coaching!
buswarrior

[luvrbus]

A good tune up on the 6v will help with a heating problem and like Boomer I have always used the 2 filter setup for the Allison it helps and keep good seal inside the thermostat housing on both sides those go bad and they play a important roll in the cooling system  

good luck

[Seville]

More great advice ! I almost feel like I should be paying for all this info.
Buswarrior, thanks for the tips. That sounds like a fix I can do myself and I can do it right away.

[Lin]

Well BW, I never looked at the huge hole around the belts.  Of course, whatever rubber block was supposed to be there is long since gone, so that hole has to be the biggest air leak by a long shot.  It really puts the entire design concept in question.  I mean, to design a cooling system that depends on an air tight compartment and then to put an opening in the compartment to a source of hot, pressurize air seems ridiculous.

[Iver]

I had a bus mechanic tell me pretty much all of them will over heat. I have never had a problem even running mountains in 100+ weather so I guess I am lucky with this 8V92   Jerry

Jerry, 
   I have often wondered if anyone running a 8v92 in a MCI could avoid overheating.  Just knowing it is possible gives me some optimism with our MC-9/8v92.
What are the details of your coach?  Injector size? Stock rads and pulley?  Careful driving?
      Just curious,  Thanks,  Iver.

[Seville]

Jerry,
Just like Ivar, I am curious of what type of set up you have in your coach?
I have heard about how bad an 8V92 can overheat.

It gives me hope for my situation.
Thanks

[LUKE at US COACH]

Hi Seville & Folks:

Just curious as to whether you have replaced the air cleaner element since you have owned the coach???

Even if only partially clogged, an MCI will start to peak on temp.  Sometimes they will warn with some black smoke.

I Hope ths HELPS!!!

Happy & SAFE!! Bussin' to All.

LUKE at US COACH

[Busted Knuckle]

Hi Seville & Folks:

Just curious as to whether you have replaced the air cleaner element since you have owned the coach???

Even if only partially clogged, an MCI will start to peak on temp.  Sometimes they will warn with some black smoke.

I Hope ths HELPS!!!

Happy & SAFE!! Bussin' to All.

LUKE at US COACH

Like is very correct on this tip! (don't ask how I know)

Also a clogged or incorrect muffler will cause problems!
FWIW
  BK 

[JohnEd]

Hi Seville & Folks:

Just curious as to whether you have replaced the air cleaner element since you have owned the coach???

Even if only partially clogged, an MCI will start to peak on temp.  Sometimes they will warn with some black smoke.

I Hope ths HELPS!!!

Happy & SAFE!! Bussin' to All.

LUKE at US COACH

The clogged or undersized air filter cut MPG and POWER and adds heat.

The fix for letting this get out of hand is the FILTER MINDER.  Costs about $35 on ebay.  No bats required and is fool proof.  If your filter starts getting restrictive....for any reason....it gives you a red warning flag.  You know that stuff about "change the filter every XXX miles" hooey?  Do not change your filter unless it is clogged and restrictive.  On the other hand...change it as soon as the thing is restrictive for any reason and that saves fuel.  With the cost of those new filters being ??  I'll bet the Minder will recoup it cost in only a couple required changes and a clogged one getting changed out will probably pay for itself in one change. 

I don't own any stock in filter minder.  I just worry about you,ns guys.  That and I NEVER hear others talk about this device.

They also make one that is cross connected that warns of crankcase over pressure.  Is there any connection between a DD 2 stroke having a positive pressure on the crank case and also being known as a oil leaker?

[JohnEd]

ok, cheap fix time.

happy coaching!
buswarrior

BW,

Great post,

This is such a very common problem and has so many people dumping money and ruining engines that I suggest it be made a sticky.  Each of your suggestions is so very valid  and at least most of it has escaped the awareness of MCI owners.

I would like to see a art. in BCM that addresses all your fixes and pics of before and after.  Would be a smart move if the mag article referenced a sticky on the BB and that would save a bunch on printing costs.  I hope you can get together with Mike on this.

I will never forget the post where the Knut just bought the MCI 9 and it over heated at 60.  He pulled off the freeway and pulled into a car wash.  There he washed out the rads from the inside of the air chamber.  Said the water cascading down the outside of his bus was thick brown MUD.  Back on the freeway and no heating problems at 70 or up hill.   That fix set him back a buck fifty so that was a long time ago.   PLEASE?

Thank you

John

[buswarrior]

I would be VERY CAREFUL with a pressure washer or high pressure hose near the radiators.

All pressure washers are NOT created equal.

You can destroy a brand new radiator, never mind a busnut special, rotted out one.

By all means, rinse the rads out, but go easy with the strength of the water blast!

Busnuts inherit coaches with problems. Many times, expensive ones.

That's why they were for sale in the first place!

That is also why we get certain issues over-reported in the hobby, like cooling trouble.

Return the coach systems to a state of good repair, and the problems go away.

happy coaching!
buswarrior

[chev49]

absolutely be careful with pressure washers n radiators (not to mention the electrical stuff). i use my hot one for equipment n vehicles every day since i "retired", and great care with low pressure must be used around the rad cores, but they can be done.. n ive done hundreds. they are an extremely valuable tool... well, not the cheap ones....