Gen2 overheating when driving slow hills

[KyleT]

No experience with a monty but other vehicles I had would overheat with no fan shroud,

I made aluminum plate and cut some vent holes in it and use rubber flaps to cover them so that at low speed it forces air through the fans and high speed wind blew them open.

Generally mechanical fans move way more air than electric ones.

I wonder if you solve your original problem but created a new one? Do you still have the ac condenser fan?

I'm a huge fan of electric fans of they will work properly.


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[Salonika]

I'll try and measure the temperature drop over my radiator parked at idle, that might at least be a decent comparison condition for you.

 

[MummifiedCircuitry]

Are you sure the fans are sucking and not blowing? I've seen it happen to people a few times that they wire them in backwards,and it is fine at a stop, and fine at speed, but it will get warm after a little bit of driving around looking for a parking space or in slow rolling traffic.

They are both mounted to the backside of the radiator and are pulling air through towards the engine, not pushing against the natural flow of air. The truck does fine in slow rolling traffic, the only time I've gotten it to overheat is on slow fairly steep inclines.

 

[MummifiedCircuitry]

When you experience the overheating, have you tried blasting the cabin heat to see if that does anything to lower temp?

I was blasting the heater when I was flushing, refilling, bleeding the system, but haven't tried running it when it begins to overheat. I'll try to replicate it today and check. I've got about a 1/4" mile driveway that is steep 10mph and it always seems to do it there, so by the time it starts overheating I'm already home.

 

[MummifiedCircuitry]

No experience with a monty but other vehicles I had would overheat with no fan shroud,

I made aluminum plate and cut some vent holes in it and use rubber flaps to cover them so that at low speed it forces air through the fans and high speed wind blew them open.

Generally mechanical fans move way more air than electric ones.

I wonder if you solve your original problem but created a new one? Do you still have the ac condenser fan?

I'm a huge fan of electric fans of they will work properly.


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I still have my original shroud, so I'll try putting it back on. I was hoping I didn't need it, I liked the extra space at the front to work with. I do still have my AC condenser fan, but it never really spins too quickly, I'd rather just wire it to always be on. If I remember correctly, on a few other cars I've had, if you snip one of the wires to the condenser fan or loop a wire it'll run on high constantly, but can't remember the details. I've installed e-fans on a few different cars and always had good results, I feel like this case is something unrelated to the fans, a gremlin that I haven't tracked down yet. Honestly, if having a shroud on/off is a deciding factor on if an engine overheats, that's a pretty crap design and hints that there is something inherently wrong with the system. Another point I might add is I have hood spacers, so lots of hot air is released from there as well. Thank you.

 

[nckwltn]

if you were overheating before the electric fan mod, I'm guessing the new setup isn't the problem.


I think there are a couple of drain plugs in the engine block... You might be able to undo them and clear out some chunks of crud. But they might be too corroded to remove. You'll have to do a little googling to figure out where they are.


The OBD2 does send an engine temp reading, if you have a code reader (I use ultragauge), you might be able to see the actual temp reading and know if you are getting into an unsafe zone vs just a rising temp. I've had my engine temp go up to 215-220 on long slow up hill crawls.... keeping the shifter in L (it kind of locks the torque converter), usually helps (but helps more to keep the tranny cool). I could hear the coolant boiling when I stop the car. The last time this happened though, I was at 8k feet... so water does boil at a lower temp.

you could also use an iphone or something to report the angle of the hill you're going up, as well as the distance. Perhaps someone else can re-create the circumstances in their location and report their results.

 

[Marutuk]

One thing that happened to our '98 when it was overheating was actually the radiator cap that was broken. I would double check that one too to be safe.

 

[sjobey]

Air pocket in system that moves forward when going up hill that limits or stops flow? At higher speed and more flow it doesn't impact temp as much? Did you bleed system to highest point? My $0.02. Good luck.


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[BOPOH]

I'm glad i found this thread, my '98 Gen 2.5 does exact same thing (except im on old system with new fluids). I hope it's not faulty design because my sport with 3.5L also runs kinda hot, both trucks are at the middle of factory temp gauge but engine bays is really hot

 

[MummifiedCircuitry]

Air pocket in system that moves forward when going up hill that limits or stops flow? At higher speed and more flow it doesn't impact temp as much? Did you bleed system to highest point? My $0.02. Good luck.


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I've owned a few BMW's that are finicky about bleeding procedures, so I've got in the habit of bleeding systems when parked on a steep incline with the front of the car elevated. I did the same with the Montero, hoping an air pocket would work it's way forward. Thank you.

 

[MummifiedCircuitry]

if you were overheating before the electric fan mod, I'm guessing the new setup isn't the problem.


I think there are a couple of drain plugs in the engine block... You might be able to undo them and clear out some chunks of crud. But they might be too corroded to remove. You'll have to do a little googling to figure out where they are.


The OBD2 does send an engine temp reading, if you have a code reader (I use ultragauge), you might be able to see the actual temp reading and know if you are getting into an unsafe zone vs just a rising temp. I've had my engine temp go up to 215-220 on long slow up hill crawls.... keeping the shifter in L (it kind of locks the torque converter), usually helps (but helps more to keep the tranny cool). I could hear the coolant boiling when I stop the car. The last time this happened though, I was at 8k feet... so water does boil at a lower temp.

you could also use an iphone or something to report the angle of the hill you're going up, as well as the distance. Perhaps someone else can re-create the circumstances in their location and report their results.

I have a code reader, but it doesn't have temp reading capabilities. I read up on drain ports on the block before I changed the radiator, and I believe you have to pull an exhaust manifold and some other components to access them. I don't know what could be left since I flushed the system multiple times, also with prestone cleaning solution.

 

[BOPOH]

just a thought, you know when you tune car on the dyno and watch air levels - if it's too high engine can running hot and blow. Could it be something related to old fuel injectors or some other issues in fuel delivery making it run lean thus causing excessive heat?

 

[MummifiedCircuitry]

Something a bit odd I just noticed as well. The truck hasn't been driven since yesterday, it was stone cold and I opened the radiator cap and it spit about 1 cup of coolant at me. Shouldn't any excess pressure/fluid be transferred to the overflow tank, especially after sitting overnight? My overflow was nowhere near full, barely 1/2" of coolant in the bottom.

 

[BEG]

Something a bit odd I just noticed as well. The truck hasn't been driven since yesterday, it was stone cold and I opened the radiator cap and it spit about 1 cup of coolant at me. Shouldn't any excess pressure/fluid be transferred to the overflow tank, especially after sitting overnight? My overflow was nowhere near full, barely 1/2" of coolant in the bottom.

Maybe there's a blockage in the little hose that runs from the radiator fill neck to the overflow bottle?

 

[MummifiedCircuitry]

Maybe there's a blockage in the little hose that runs from the radiator fill neck to the overflow bottle?

There's not, I've checked probably 5 times, last time about 30 seconds ago. I can blow in both sides of the hose and there's nothing clogging it, very strange. Could the radiator cap be preventing fluid from going into the overflow? I removed the cap from the overflow and coolant still wouldn't come through until I loosened the radiator cap, then some rushed out of the overflow line.