1980 International S-1700 school bus coolant leak problem

I went to fill the radiator with water and it immediately leaks out of a grate on the transmission bellhousing. There may be a cracked freeze plug behind the flywheel. Not sure if if would be easiest to remove the transmission or the engine itself to try and fix the problem. Any suggestions are very welcome!

Category:

Autos & Vehicles

Tags:

• 1980
• International
• S-1700
• school
• bus
• coolant
• leak
• problem
• freeze
• plugs

[kjm1983]

I might add that frost(freeze)plus usually fail for 2 reasons: They rust through because of poor cooling system maintenance, or they pop out because the coolant froze up due to lack of enough antifreeze. I don't mean to sound alarms, but that trans WILL have to come out to repair this issue if its not just a leak from a hose up top.

[retrochad]

The weird thing is that there is no regular radiator filler cap on the radiator. One time I saw an IH Diesel bus where there was a reserve tank spliced into the hose going from the top of the radiator and that's where the cap was. There was just a weird fitting that screwed into a little hole on top of the radiator, and removing that allowed me to pour water in. I wonder if the original radiator cap system was removed and the coolant wasn't changed for many many years?

[kjm1983]

The heater core should be inside the bus with the heater box. This sounds like a rusted out freeze plug issue, and usually the trans is dropped out to access it. I strongly suggest getting the engine running enough first to make sure it's not knocking or smoking or doing something else bad before you do an involved job like the freeze plugs.

It won't hurt it as long as you don't run it longer than about 5 minutes at a stretch.

[retrochad]

Thanks for your advice...I put all new spark plugs in it and hooked the plug wires back up and then went to fill the radiator with water and that's when I noticed the problem. I was afraid of damaging something by trying to start it up with very little coolant in it but I'll give it a short test.

[Strasburg1991]

@retrochad did you try to crack an egg into it, it actually works

[lawnboy531]

yeah, u might have a freeze plug out, cause thats what happened to me and

my truck, i had a 47 international road tractor and the i started to pour water in the

radiator and it was spilling out of the side of the engine block so that could be it,

it's weird thay would not have a cap on the radiator though

any questions ask me

mike

[hippieman65]

get a mechanic to come and look at that bus engine. i think it is a crack in the engine block.

[bamaslamma1003]

Did you ever get it fixed? I'd like to see this one run.

[BusDriverStevo]

chad we have a 79 404 at r rafting center i checked it does have a reserve tank i think yours did to when it was new

[backwoods3214]

leak stop i use dont plug radaitor or hater cores, i been useing it for 30 years. ive even seen it recomended under warenty and some manufacturers put in at factory. if its inaccessible location

cracked. or worn then fine,

were not trying to fix a heater or rad.

a plug in a inaccessible location .

or crack.

[DieselsAndDiodes]

a bad freeze plug in an inaccessible location is one of my least favorite things. hope it isn't too bad to fix.

[kaiyoshi2243]

Yeah, Looks like either a bad freeze plug on the back of the engine block or a blown head gasket that is leaking out of the back of the motor and running down and around the transmission bell housing. And I also agree with kjm1983. I would never use leak stop or any other kind of "quick fix"

Well.. there's my 2 cents. Good luck!

[kaiyoshi2243]

I've been giving this some thought. I think your bus is suppose to have a reserve coolant tank. And that tank would have attached to that "weird fitting" on top of the radiator. Probably the tank rusted or started leaking and the previous owner just removed the tank. Which is not a good idea, no way to check the fluid level., but would work in a pinch.

[kevykev38]

I wouldn't use a stop leak . Stop leak is known to clog heater cores and radiators. Replacing a freeze plug would be the thing to do. Good Luck!