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Hi running temps?

VB242

VB242

I.M. Weasel
Joined
Sep 21, 2011
Location
Driving the No Malarkey Bus
I noticed the past couple of times that I was boosting hard in 4th and 5th gear that my temp gauge gets almost in the red, I turned on the heat this morning and brought the temp down back to the normal range. I'm running the water cooled oil cooler off a 940 but have a stock aluminum 240 jy radiator. Do I need to switch back to air/oil setup or get a better radiator? The thermostat is newish, and it seems to hold normal on the low end. Coolant is full, water pump belts are tight.
 
you could have blown the head gasket out. some auto parts stores have a coolant test kit that will detect combustion products in your coolant to check your head gasket.
 
I suppose it's possible, I'm running a Cometic though, maybe a small crack in the head? It did it again this morning, only at high speed, high boost, coolant is a little low. No visible exhaust emissions though. It seemed to cool off quickly once I removed the coolant reservoir cap. I will get the test kit and chiggedy check it out.
 
[1st things 1st.......... Does the 940 have the temp faker WT gauge?

In other words.....Is it the *"temp faker" temperature compensator board type*?

If so they can fool you into thinking you're having an intermittent (usually when they first start to fail) or a constant(when they really go to pieces) *false* overheat condition when there really isn't one.

My 91 240 N/A played this trick on me too and it started by temporarily /intermittently giving a *false* slight overheat condition, then late rthey lasted a bit longer. Mine was *always* intermittent though.

This after replacing t stat, WP, all hoses, radiator, fan clutch , new belts , cleaned pullys new HB,



have you by pass the compensator temp board already, or have not?
 
If your temp gauge is going up in boost and goes away when it cools back down your engine is detonating like crazy. The huge amount of heat from detonation goes right into your block and head.

Add fuel, reduce timing, rinse, lather, repeat.
 
smokeyfan1000 said:
[1st things 1st.......... Does the 940 have the temp faker WT gauge?

In other words.....Is it the *"temp faker" temperature compensator board type*?

If so they can fool you into thinking you're having an intermittent (usually when they first start to fail) or a constant(when they really go to pieces) *false* overheat condition when there really isn't one.

My 91 240 N/A played this trick on me too and it started by temporarily /intermittently giving a *false* slight overheat condition, then late rthey lasted a bit longer. Mine was *always* intermittent though.

This after replacing t stat, WP, all hoses, radiator, fan clutch , new belts , cleaned pullys new HB,



have you by pass the compensator temp board already, or have not?
Click to expand...

I have not bypassed the temp faker circuit, but I did replace the little doohickey on the back of the panel '06 ish.
 
740atl said:
If your temp gauge is going up in boost and goes away when it cools back down your engine is detonating like crazy. The huge amount of heat from detonation goes right into your block and head.

Add fuel, reduce timing, rinse, lather, repeat.
Click to expand...

I don't hear anything, but you may be right as well. I will add a little fuel and see what happens.
 
You're running lh2.2, can you back off the timing?
How much boost are you running?
What plugs are you running?
 
mafoose said:
You're running lh2.2, can you back off the timing?
How much boost are you running?
What plugs are you running?
Click to expand...

I could it's at 12degree BTDC right now.
16 psi
NGK's in stock heat range BPR6 something's

I bought a new thermostat at lunch, will install this afternoon, it seems funny that the heater circuit takes the heat right out and the temp is actually a little low when it cools off, maybe I have a stuck thermostat.... it was a $4.00 one from Rock Auto.
 
You have now burdened your cooling system with engine oil heat as well.

Look at the size of a 940T radiator. They increased in size substantially with the addition of the water/oil exchanger
 
740atl said:
If your temp gauge is going up in boost and goes away when it cools back down your engine is detonating like crazy. The huge amount of heat from detonation goes right into your block and head.

Add fuel, reduce timing, rinse, lather, repeat.
Click to expand...

This guy was right, turned down the boost to 13 turned up the fuel, seems better, hopefully I won't have to pull the head.
 
What do y'all think about re-torqueing the head bolts? It seems fine until I really get into boost, I am running a Cometic, perhaps a little more squeeze will hold it together a little while longer, maybe use the Penta 120 degree turn spec?
 
VB242 said:
I could it's at 12degree BTDC right now.
16 psi
NGK's in stock heat range BPR6 something's

I bought a new thermostat at lunch, will install this afternoon, it seems funny that the heater circuit takes the heat right out and the temp is actually a little low when it cools off, maybe I have a stuck thermostat.... it was a $4.00 one from Rock Auto.
Click to expand...

You can try going a heat range colder. BPR7ES gapped at .028. Back off the timing a degree or too if that doesn't help. It sounds like you might be running out of fuel. Weak fuel pump?
 
No I actually think I'm getting some kind of combustion bypassing into the cooling system but only at 15" when I keep it around 10" I don't have any problems. No evidence of coolant in the cylinders or going out the tailpipe, it just overheats and blows water out of the coolant tank cap once I start boosting hard (15" or so). There's some minor foaming and bubbles when I remove the cap. Oil is a like new clear condition. No oil in anti-freeze either, so I'm hoping the head is just lifting a little and letting some pressure by the MLS head gasket.
 
VB242 said:
What do y'all think about re-torqueing the head bolts? It seems fine until I really get into boost, I am running a Cometic, perhaps a little more squeeze will hold it together a little while longer, maybe use the Penta 120 degree turn spec?
Click to expand...

Are you serious? Stop detonating! Fix the problem (too little fuel or too much timing).
 
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