Overheat 1966 1407 serial 535, Just Purchased

[TrentAiken]

I just purchased this bus and it overheated on the first test run.  It hit about 250 before I noticed and shut it down.  A temp gun showed a little lower.  Turns out it did not have enough coolant though there had been some in the barrel (?).

Subsequent runs of 10 miles.  No signs of anything but I have not done any "testing" per say.

What should I look for?

[OneLapper]

Hi Trent,

First off, welcome!  I'm sure you've already discovered that there's lots of great info on this forum. 

Over heating can be a simple issue such as air trapped in the cooling & heating system OR it can be the beginning of getting to know your new 8V71 intimately! 

Using an Infra Red temp gun is a great way to locate issues, so you're using the right tool.  Here are some questions that people will ask:

What's your name?
Where are you from?
Is your coach still seated or converted already?
Spicer or Automatic?  (auto will add heat load)
Condition of the radiator?
Does the torus drive for the fan work properly?
Does it have the OTR heating and drivers heat?
Does it over heat just idling?


All this assumes that you've filled up the cooling system and addressed any leaks.

Start collecting as much info as you can take in.  People will start chiming in on the post, but don't forget to take some time to search the forum for previous posts on over heating.  I'm certain you'll find dozens of topics and most everyone is pretty good of following up on their posts when the problem is solved.

Good luck!  And don't get overwhelmed! 

Mark

[luvrbus]

Pay close attention to air box drains if you see a mixture of water and oil then you have damage, if I remember the 4107 uses a direct drive fan not the torus system or they could use both not real sure

[TrentAiken]

Thanks Mark,

An answer to the questions posted:

What's your name?  Trent Aiken
Where are you from?  Currently living in Tooele Utah, close to Salt Lake City
Is your coach still seated or converted already?  Converted already but boy does it need a refresh... burnt orange carpet
Spicer or Automatic?  (auto will add heat load)  Automatic
Condition of the radiator?  Noted signs of leaking at the base of the radiator core
Does the torus drive for the fan work properly? The fan turns... I have not dove into the torus mechanism so a bit dumb in that region
Does it have the OTR heating and drivers heat?  Drivers heat
Does it over heat just idling?  No over heating now that I filled up the fluids.  I suspect it was a air lock

[OneLapper]

Woohoo!  Solved just like that!  LOL!

I've seen more than a few conversions with burnt orange, yellow and purple shag carpets!  One of the more recent ones was a professionally converted 4106 that had organge shag carpets, yellow counter tops, and a orange wall fabric.  It looked like a New England autum vomitted inside that poor bus......

Keep us posted on your progress.

Mark

[gus]

I just purchased this bus and it overheated on the first test run.  It hit about 250 before I noticed and shut it down.  A temp gun showed a little lower.  Turns out it did not have enough coolant though there had been some in the barrel (?).

Subsequent runs of 10 miles.  No signs of anything but I have not done any "testing" per say.

What should I look for?

Get a service manual. This is the only safe way to operate this bus, it, like most GMs, has a number of things very different than the offbrands:)

There are two air vents atop the engine that need to be used after a low coolant event.

[Dave5Cs]

Before you start it up check all your fluids. If they are low check for leaks and if it was low why did it not shut down automatically. Tells us that your shutdowns are not working or hooked up? check those first. You also have one for the oil. It will be a round sensor with 2 screw on fittings for wires coming out of the top. Oil will be generally on a rail with some other things on it on a GM I don't know where the coolant one is, someone else might chime in on that.

[MightyThor]

Used to drive Demo derby cars.  We run them till they get hot then run them some more till they quit.  I have had engines so hot they glowed.  But after cooling off we have had many engines that fired back up and ran ok.  Here is what I can tell you.  A mostly Cast Iron engine can survive some horrible overheating.  When things get hot they get bigger and that makes some things really tight like piston to cylinder clearance, bearing to crank or Rod, etc.  If things are shut down before the parts touch, you may be good to go. 

When things get hot it also screws up seals, and other parts that should not be that hot so you can get leaks etc.  But if you don't have leaks you may also be ok. 

When things get hot the fluids, in particular the oil, break down and do not perform to spec.  This can then cause other failures.  Anytime you have had an engine hot change the oil. 

I don't mean to suggest that a hot engine can't suffer damage, not uncommon for things to warp as they cool off, even more so if you try to hasten the cooling by pouring things into a hot engine to "cool it off"  Also, the different rate of expansion and contraction of Steel vs Aluminum also often results in warped or cracked parts. 

250 is hot, but Ive done worse and driven away an hour later.

[luvrbus]

Wonder what the actual temp was at 250, the 8v71 is well done especially on a GM the upper head will usually go around 220 to 225 degrees I guess he will tell us in time   

[robertglines1]

metric gauge?   I don't know exact but in speed 100 on speedo was only around 55 mph.

[TrentAiken]

The coolant was at a boil so we know the minimum temperature.  When I checked head temperature with the temp gun they were 202, block 210, hottest was fan hub 220.

I let it run and slowly added coolant while misting the radiator. Hopefully the DD gods smiled upon me.  I drove it around the following day.

Time for fluid change

[luvrbus]

Good those temps won't hurt it the temp never reached the the 205 warning or the 215 shutdown the block heat and fan drive wasn't bad the oil temp added to that and 220 is not bad for oil temperature that is in the normal range of 200-250 degrees 

[gus]

The coolant was at a boil so we know the minimum temperature.  When I checked head temperature with the temp gun they were 202, block 210, hottest was fan hub 220.

I let it run and slowly added coolant while misting the radiator. Hopefully the DD gods smiled upon me.  I drove it around the following day.

Time for fluid change

Check your temps at the hose inlets where the temp gage sensors are located with a IR temp tool, this is the only way to compare the two. I usually check the metal fittings at the radiator too and they are very close to the engine temps.

My temp gage is always higher. that the actual engine temp.

These engines can take a lot of abuse.

[MightyThor]

And as a gauge of how hot things will run, all of my current emissions engines in my Jeep vehicles (I have more than 5) all run at a minimum of 210 degrees on the gauge when at proper operating temp.  That means the heads and block are warmer in many spots.  this helps the engine burn clean and make more power.  With the numbers you gave I am pretty confident that you didn't hurt much if anything and I would just change oil and keep an eye out for anything unusual.

[luvrbus]

Don't always trust the IR guns unless you have a good one with adjustable emissivity and a good distance to spot  cheap guns will get you in the ball park but don't bank on it being accurate  

The H/F crap is terrible buy a decent brand like a Rayek,Fluke,Extech or other brands with a adjustable emissivity and a good distance to spot.
I paid 200 bucks for my Extech with dual lasers and a distance to spot of 12 ft it made a believer out of me the difference in it and my old Master Cool gun  

It took me a while to figure it out being a slow learner shooting a turbo housing I knew should have been around 900 degrees and the gun was reading 625 lol that was because it was as high as the Master Cool would read at 4 ft distance to spot