Buttoned everything up today and took her out for a test drive. She overheated. Wouldn't cool down. Went to the back and noticed hose clamp broke. Is my thermostat stuck and causing extra pressure buildup causing the overheat and clamps to blow and blowing my last old radiators?
https://vimeo.com/110160319 (https://vimeo.com/110160319)
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And can anyone give me a tutorial on replacing the Tstats? I assume I remove the four bolts on top of the housings?
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Sounds more like a air lock or pocket to me if it was doing it before I would check the T stats and the seal inside the housing if that doesn't cure it check for a loose impeller on the water pump they are bad about coming loose if not locked with a punch.
There should be a 7 lb relief valve on the surge tank for the pressure control maybe it leaked and someone removed it and plugged the tank
Watch the 4 bolts on the housings soak good with PB and take your time those will twist off then it is drill and tap time not much fun always try to tighten 1st then try to remove works the best for me
Exact thing happened to me once a while back it was traced back to the water pump , replaced pump and thermostats and all was fine
Scott, buy or borrow an IR gun and shoot the inlet and outlet of the t stats, the radiators for cool or hot spots and the water pump. You can also shoot the exhaust manifold to see of you have a cylinder/head gasket issue.
Could've saved a lot of money a few years back when I was overheating if I would've suggested that to the mechanic who was dumbfounded as to why my motor was overheating.
Don't shoot it at reflective surfaces as it ill give you false readings
RB
I have a temp gun, so I'll fill with water, buying a new hose clamp right now and then I'll check to see if there are discrepancies in the temp before and after. Annoying because I just had it at ww Williams to ask about the overheat issue. They dynoed the bus and said it wasn't overheating. Frustrating because I can't limp it back to them if it's overheating so I'm stuck doing this myself with 2 weeks before we leave...
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You just changed the antifreeze I would bet on a air lock a Dyno will heat one up in a hurry ::)If it left the dyno not heating then it is a minor problem
sounds like an air lock to me too...quite common when you change 20 gallons of coolant...
find a way to bleed the system...
let it idle and circulate for as long as it isn't over heating..
did you change the coolant and simply drive off...
what did it dyno at... we need numbers ... :)
i would run the air out before i tore in to the t-stats....
Make sure all your seals around the rads and air box are in working condition.
Just a thought.......check that the fans are firmly secured to the shaft on the blower assembly.
A local friend has an MC-2 that has rubber isolating bushings in the blower shafts on his bus.
One of the rubbers had failed, but you couldn't see it. Both fans seemed to move air down over the engine just fine at idle; but one of the fans was essentially freewheeling when it came under load ( increased rpm ).
Bus ran fine up to about 50mph then would start heating. He replaced thermostats and hoses with no improvement.
He somehow stumbled upon the loose fan and failed isolating block.
All is well after a $20 fix.
I am betting on a air pocket, air expands a lot compared to water, thusly the broke clamp
Don't know if your engine has a valve and cylinder to control belt tension but on my 8V92TA had prevost service all fluids including radiator (antifreeze) and they left valve almost closed. Would run at low speeds but hit intestate at higher rpm and it would heat up and scared me to death. Limped home and my Tech found valve shut. Couldn't tell at idle looked okay to me. Slipped at speed. Just a thought.
I know that I am talking through a hole in my hat because I have never had one of your thermostats in my hand. That being said, like others, I wouldn't be surprised to see an air lock. Over the years I have seen that happen on a wide variety of vehicles--particularly those with a heater core higher up than the thermostat. I now drill one or two 1/8" holes in every new thermostat flange and position them at the "top" of the housing to help burp the air. Not an original idea as I've purchased several t-stats so equipped but it sure has helped. I also pinch and release the upper hose as I fill the system to encourage a good burp. Jack
Thank you very much all of you. Chasing this down... And taking all the advice. I let the coach cool, I then opened the coolant fill door and it was under a lot of suction. I added three more gallons of distilled water. I then ran the coach up to temp and let it cool and added another gallon. The next time I started it and ran it I couldn't get it to overheat. But I haven't driven it yet, just left ebrake applied and let it idle under the "load" of the brakes. That overheated it the first time but after adding the 4 gallons of coolant I can't get it to overheat now. It was 75 degrees today just for reference. Tomorrow it will be 60 and I'll test drive it but I'm bringing several gallons of coolant and water with me. I bought a heavy duty tbolt type clamp to replace the broken cheapo worm clamp and it doesn't appear to be leaking any coolant now at that hose. The air pocket expanding and causing the burst hose theory makes sense to me. As for the air piston for the belt, mine is stiff and I have to manually pull on it to get full belt tension. How do I adjust the air cylinder pressure? Also, I do need to finish installing all the radiator seals. Tomorrow I'll make that happen, test drive and see what comes. I'll also check for loose fan cages. I've checked them before and they didn't freewheel but I'll check again. Thank you again guys. You're a great group and I'm thankful
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7 gallons is a lot... did you lose any on the overheat ?
The air pressure for the belt tensioning cylinder is set by a pressure regulator just in behind the belts on my MCI. There is a valve that turns the air on and off, or releases it completely, and the pressure regulator is right beside it, then the hose goes to the air cylinder so you can trace it back. My manual specs out a Williams WM-279-E1 regulator set at 21 psi.
Brian
Ok thanks Brian. I'll check that today. Eagle, I added 4 total not 7. Sorry for the confusion
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Run it up to temp it in your case above and let it sit overnight and top it off. It should be ok and any air pocket will have risen to the highest point.
Worked for me!
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OK Scott several things come to mind here.
1st off as Yoda 1st mentioned it's most likely an air pocket.
Now you may have already burped that pocket out. But just to be sure check all over the top of your engine and see if any of the crossover pipes have petcocks in them. (usually pointed straight up)
If so run it up to temp then carefully open the petcocks and see if just coolant comes out or air, or both. I usually do this 2-3 times after draining and refilling one so as to be sure all air is out.
2nd you mention that you have to pull on your belt tensioner to get it to come tight? there is a problem there.
It could be as simple as the valve accidentally being in the position. But more than likely the valve, regulator, cylinder, or pivot points are the culprit.
If it is a valve or regulator you should be able to determine and fix fairly easy. (rebuild or replace)
If it's the cylinder they can be rebuilt, replaced or eliminated. (a proper size turn buckle solves the whole air problem and is tight all the time!
If it's froze up pivot points then you have to do some dis-assembly and get them freed up. Then as you put them back together grease the snot out of them! (they should have grease fittings already on them but are very commonly over looked by many "mechanics" when servicing!)
Also mentioned we the fans and seals which of course can leak and be part of the problem.
And yes even the water pump can play into all this too.
;D BK ;D
Ok. Thanks again gents. I have been driving today. Warmed it up to temp and let cool several times and added water/coolant. So far, since initial fill of coolant system post radiator install, I've put in 7 gallons now total. So yeah, it was thirsty. Air pocket I'm sure like most of you have suggested. It's now running much cooler. A coupe times its approached 200 but hasn't actually reached it. Going to let it cool again and see if I can add more coolant. Radiator seals are solid now and I'll be checking the fan belt air cylinder
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Ok. Things are definitely better. Must have been air. Freaked
Me out. I'm a self proclaimed bus hypochondriac....(https://busconversionmagazine.com/forum/proxy.php?request=http%3A%2F%2Ftapatalk.imageshack.com%2Fv2%2F14%2F10%2F28%2F388d9a4c33e5af44463e6981efa68cd2.jpg&hash=5f1313ec19556b1be53d7b7e95e2fcdd1488db85)
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Quote from: Scott Bennett on October 28, 2014, 02:35:30 PM
I'm a self proclaimed bus hypochondriac....
Glad that worked out, Scott. Even though i know better, part of me assumes a blown engine or transmission at the slightest noise or vibration.
Maybe they have a program for me at the Henry Ford Clinic.
Lol. If they started a program like that, I'd be attending alongside you. I think gumpy mentioned that your rads are sealed pretty good if you can do this...and btw, this rag was wet and heavy:
https://vimeo.com/110357423 (https://vimeo.com/110357423)
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Now you have all the air from the system let the level find it's happy place and keep it there or you will be adding coolant all the time because it will just blow it out till it finds the happy place it likes
Advice taken. Will do...
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I use 40 weight!.... ::)
The 1989 service manual for MCI MC9 calls for 10W40 for the power steering system.
Don
I'm confused
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Quote from: Scott Bennett on October 30, 2014, 04:14:37 AM
I'm confused
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They jest be'n smartalics!
But on that note I use Delvac 15/40 in all my buses an Sprinter Van now!
(of course all our buses now run 60 Series an the Sprinter has the 2.7 5 cyl turbo Mercedes diesel)
;D BK ;D
you guys are killing me... :)
Scott- at least you know what's killing you, the rest of them don't have a clue ;-)
Niles ole buddy where have you been?
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Not looking for another hole in the ground to throw money into, but I'm keeping my eye on you, keep the faith and good luck, just have pity on me and don't blow the doors off me in your new truck. First one to the fuel island pays the tab.
Best way to get air out is leave filler cap un latched run up to temp shut down & top off.
Lol. Thanks niles ;). Itspaidfor, I wasn't sure if doing that would cause precious expensive detroit power cool to come flowing out of the reservoir if I did that so I refrained. But yeah, I think it would have been faster.
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Don't forget you still have a problem with the belt tensioner that WILL cause grief in the future unless it is fixed.
Thanks for the reminder tony. It's going on the list :)
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QuoteIt's going on the list
Yes, I have one of those lists too. Never gets shorter though.