8v71 overheating

desi arnaz · June 15, 2012, 03:30:48 AM

Help, please! My 4106 seems to be overheating, I fill the tank and a few miles later it is empty and I hear gurgles. I don't see any real signs of a leak Could I have a sticky thermostat? An air lock? I may be low on coolant but that shouldent be a problem as I have traveled from buffalo to new Hampshire on straight water and never got above 170. We are sitting in a campground in st johnsbury on the way to the granby zoo in Quebec and I need some answers..... Also where is the thermostat located? How hard is it to replace? Thanks!!!

Nusa · June 15, 2012, 04:37:10 AM

First thing would be to check for signs of coolant in the oil. If you find any, I'd read this thread: http://www.busconversions.com/bbs/index.php?topic=23052.0

RickB · June 15, 2012, 05:34:59 AM

Sounds like a head gasket... Hope I'm wrong.
Rick

OneLapper · June 15, 2012, 06:13:21 AM

Desi,

The thermostat housing is on the upper most part of the engine. A hose from the coolant tank goes into the top of it.

What engine temps did you see?

Mark

RickB · June 15, 2012, 11:14:23 AM

Borrow an infrared thermometer from someone if you don't have one. Shoot each cylinder as it's running you'll probably find one that's running at a completely different temp, that would be the one. Check your coolant for oil and your oil for coolant.

RB

RickB · June 15, 2012, 11:15:51 AM

While you're at it shoot the inlet and outlet of the thermostat housing. pretty easy to tell if the water is cool on the inlet side and hot on the outlet that its a stuck thermostat. Shoot the radiators too.

gus · June 15, 2012, 01:42:30 PM

An infrared thermometer is a must have tool. My heat gage is so far off and erratic I use my IR thermo all the time to check it.

I have boiled out my coolant tank more than once thinking I was running just fine. Now I never take the heat gage for granted.

fortyniner · June 15, 2012, 05:41:34 PM

Hey Gus, where is a good place to check the 8v71 temperature?

-Tom P.

OneLapper · June 15, 2012, 06:55:45 PM

Ummmm, it's not Gus.... But the best place to check the temps are at the thermostat housing.

luvrbus · June 15, 2012, 07:08:00 PM

Me I would check the goofy fan the GM's uses and make sure the fan is working if not by pass the valve like 99% have done

good luck

baker4106 · June 15, 2012, 07:20:40 PM

My 4106 does not have a hydraulic drive fan but a direct drive fan. Do not remove the thermostats if they are bypass ones. Had the same problem with my 4106 and found the heads cracked and exhaust gases were pushing the coolant out of the expansion tank. Check the oil for coolant or remove the fill cap and look for moisture on the inside of the oil fill cap.

luvrbus · June 15, 2012, 08:16:57 PM

Just giving him a option if he has the Torus fan you see a lot of those on the 4106 when working they work great and he didn't say what fan he had

desi arnaz · June 16, 2012, 02:43:17 AM

Well my gauge said 180 so I thought I was ok, not.....damn thing died going up a hill.found I had no coolant so I went and got $200 wort of coolant ,I installed it it starte ran a little rough I went half a mile and it started to spit the coolant out and and make a boiling sound in the resivioour. We had her towed to a local garage, the guy will be Abel to look at her and give me some idea. Oil was black but inside of cap looked whiteish.drivers were fantastic! First driver. Was sent wit a wrecker big enough for a west falls, second was a real wrecker.first guy waited around to help other guy. Offered if bus was unfixxeable I could store it at his house while I stripped the good stuff off. My feeling is this started during winter when I thought I had enough coolant in her. Might of been just a freeze plug,we can't find where the leak is yet.

gus · June 16, 2012, 09:43:08 PM

OneLapper is surely correct but I check mine there and a half dozen other places just to make sure, also on the AT housing.

To compare the IF reading with the dash gage check it at the same place as the gage sender.

Please note that these IF thermos are supposed to be held at specific distances depending on the area being measured.

That being said, I don't find it makes a lot of difference unless the surface is very small or shiny or rubber. Rubber gives a completely false reading.

I also use them to check tires and wheel hubs. If there is a big difference in any of them I try to figure out the reason.

luvrbus · June 17, 2012, 08:32:15 AM

I check the GM's at the T housing and both heads at the back easy to do on a GM and on a hand IR the Emissivity setting is more important than the spot distance to me.

I have saw people checking with a HF IR with no emissivity setting it wasn't even close on some surfaces