Author Topic: Off-road Overheating Issues  (Read 1954 times)

JakeP

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Off-road Overheating Issues
« on: July 14, 2018, 06:13:23 PM »
Hey team! Going to post this and see if I can get some help with the issue. A couple of weeks ago, I was on Imogene Pass. On the climb, temps skyrocketed and dealt with overheating pretty much the whole way up. I was properly in 4lo, and turned the heat on full blast.  Fast forward to today, and four wheeling a little closer to town, nothing as wild as Imogene, but same thing. Began overheating, but this time it stalled on me, 3 times. 3rd time almost didn't start again. Also my buddy noticed puffs of white smoke, but just sporadic.

I checked the oil and it does not appear as if coolant is mixing in. Oil level is fine, coolant level is fine. This is a 98 WE, with 208K. Thinking I may need to replace my radiator with a high performance one and add an electric fan. But I'm hoping I haven't created a catastrophic issue, i.e. head gasket. What are your thoughts? This is my daily, I have no issues with overheating at all unless I'm four wheeling. I just drove it to CA and through the Nevada desert, no issue.

Shovel

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Re: Off-road Overheating Issues
« Reply #1 on: July 15, 2018, 07:20:42 AM »
Oem radiator?  Been rodded out ever?

TOASTY

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Re: Off-road Overheating Issues
« Reply #2 on: July 15, 2018, 09:41:03 AM »
I've seen these things severely over heated and not blow a head gasket BUT i will say it sounds like you pushed yours a bit and now are in head gasket denial. This is the first step to head gasket replacement and possibly head repair/replace.

 In the future, stay OEM on your cooling system; thermostat, fan clutch, water pump (Aisin) and OEM or better radiator.
 Electric fans help a lot too but what tires and gears are you running?

JakeP

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Re: Off-road Overheating Issues
« Reply #3 on: July 15, 2018, 12:06:59 PM »
It is the original radiator and I have never had it rodded out in my two years of ownership. Tires are 265/75 16, gears are the OEM for winter edition, I believe 4.10s. As far as I am aware, all parts in the cooling system are original.

Toasty - What do you think next steps would be in this case? I have driven it all day and have had no issues.

TOASTY

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Re: Off-road Overheating Issues
« Reply #4 on: July 15, 2018, 02:53:27 PM »
If it's still fine, you should R&R the cooling system.

Shovel

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Re: Off-road Overheating Issues
« Reply #5 on: July 15, 2018, 03:43:46 PM »
It is the original radiator and I have never had it rodded out in my two years of ownership. Tires are 265/75 16, gears are the OEM for winter edition, I believe 4.10s. As far as I am aware, all parts in the cooling system are original.

Toasty - What do you think next steps would be in this case? I have driven it all day and have had no issues.

31.5" tires, stock gears,  no recent cooling system maintenance.    These trucks are decades old. your radiator needs to be professionally de-gacked (rodded) ,  cooling system needs a thermostat and radiator cap that weren't built before Google existed.   

JakeP

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Re: Off-road Overheating Issues
« Reply #6 on: July 15, 2018, 05:22:01 PM »
Thanks Toasty, will do.

Shovel - I drained and filled coolant when purchased. But I will take your advice on the thermo and cap, get those on order tomorrow. I'll also get on the horn with some radiator shops to get mine rodded as well, I have never heard of this procedure, that's new to me.

Rest assured, this truck has not been neglected. I drained and filled all fluids upon purchase and at 210K will be performing essentially my 30K since it was baselined when purchased. I use all OEM fluids. Thanks for the help, will provide updates shortly!

Shovel

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Re: Off-road Overheating Issues
« Reply #7 on: July 15, 2018, 06:34:02 PM »
I'll also get on the horn with some radiator shops to get mine rodded as well, I have never heard of this procedure, that's new to me.

I don't want to come across as a jerk,  we just see a ton of "my car is overheating I can't figure out why!"  and then when somebody actually looks at the cooling system in question it's full of rocky road ice cream,  has a rag stuffed in the place where the cap should be...  well you get the picture.

In all seriousness the stock cooling system is very much sufficient for keeping a stock Montero cool under just about every Earthly condition so if yours isn't keeping its cool the answer really is to figure out what has failed, not just assume it needs to be beefed up.    You can beef it up too but if you don't address the actual cause then you'll still have a problem and will have wasted money on an "upgrade" that isn't.

Big tires and long steep climbs with stock gears can stress out an otherwise flawless cooling system but you're on something like 31.5" tires,  that's not really enough to be a problem on its own.    Stock gearing for a Gen 2.5 is 4.27:1

These trucks are engineered a little bit differently than American trucks but they're not mysterious and they don't work under different laws of physics.   The same causes produce the same results really. 

The service of having a radiator rodded means a radiator shop throws the whole unit in an oven and melts the solder off the upper and lower tanks, inspects them (hopefully) - and runs a "rod" down each of the coolant tubes to eliminate accretions of build-up that might restrict flow.   Then they solder/braze the caps back on.   Around  here that service is under $100 generally. You can look inside the radiator cap with a flashlight and see if the four or five tubes visible there look clean as a whistle or if they have crusty build-up.     

So here are the things to check:

  • Ensure that your coolant system is clean and flowing without obstruction.   It's difficult to inspect the water pump itself but you can inspect the thermostat (if you have never replaced it, just replace it.)    Official lore says to buy OEM only but I'm running a MotoRad Failsafe and not experiencing any problems with it.    Either way the OEM temp is 180F,  five degrees in either direction is probably not going to ever be detrimental.
  • Ensure the radiator cap is holding pressure.   Why does this matter?   Raises the boiling point, remember that your cylinders are jacketed in water and if the water's boiling around there and around the exhaust ports that water can't effectively conduct heat away because it's insulated by the bubbles.   The other reason a radiator cap should be in good working order (not dirty, not dry rotted seals) is so that it can properly push the heat-expanded water out into the overflow tank and then draw it back in once it's cooled.
  • Ensure that your coolant is clean and the correct blend of coolant and water.   I just use Prestone and distilled water.   Corrosion pretty much doesn't happen if you use distilled and good coolant and stay on top of maintaining it every couple years.    I also like to dump out and wash out the overflow tank periodically and refill with coolant/water mix because what few impurities do cycle around tend to make their way into that tank and gather there
  • Ensure your engine is running well.  Incorrect air/fuel ratio can raise engine temperatures,  incorrect lubrication can raise engine temperatures,  damaged exhaust system or catalyst can raise engine temperatures.   If you have a check engine light on,  those can and should be diagnosed.
  • Ensure that your transmission is working correctly, has fresh clean red (or pink) transmission fluid and that your TV cable is adjusted correctly & TPS is not faulty.  The transmission is cooled by both a radiator in front of your engine's radiator and by a wet heat exchanger inside your radiator's bottom tank so a malfunctioning or stressed transmission will be dumping a lot of heat into the engine's cooling system.   Not good for the long term outlook of the trans, either.
  • Ensure that your engine cooling fan is working correctly.   There is a thermo-hydraulic clutch between the engine and the fan which can fail - it's a little difficult to diagnose but when your engine's up to full operating temperature and you rev the engine there should be a "jet engine" sound from the fan,  and if you shut off the engine while hot the fan should not keep freewheeling after the engine stops, should not be super easy to turn by hand while the engine is hot (but off, obviously.. don't touch a fan while the engine's running!).  Replacement fan clutches are neither tremendously expensive nor difficult to replace.   Inspect the nylon fan blades near their base for cracks.. those cracks themselves don't cause a heat problem but you'll want to replace that fan before it shatters the rest of the way.
  • Ensure that your engine aux fan is working correctly.    Really easy, turn on the vehicle and air conditioner, the electric fan should also be running in front of the radiator.    If it's not,  check for 12V at the connector with a multimeter.    If there is 12V at the connector and the fan's not turning, you need a replacement fan.
  • Use an engine monitoring tool like Torque or whatever's available to you to check on engine behavior during a drive cycle, like see if it's trimming fuel way forward at heavy throttle (less than WOT) and high RPM for example,  or if misfires are happening under load.   These could indicate a fuel pressure problem that would make it run lean during periods of heavy demand.   Lean combustion is hot combustion and in addition to not being particularly good for your engine temps it also can damage your valves, o2 sensors and catalysts over time.   May be as simple as a plugged fuel filter..
  • If all of the above checks out you may wish to drain your coolant into a clean container and check it for solids (grains of dirt, rust, whatever crud...)  and also drain the engine block on both sides.   Near the motor mount on the block there are threaded block drains on each side,  if the engine has been subjected to crap there might be some solids in there,  and if there's some there's a lot.   You'll want to try flushing it a few times - distilled water and commercially available engine coolant flush is the wise DIY choice.. and  you might even have to go as far as to replace the water pump too - which means timing belt, tensioner, because you may as well by the time you've gone that far in there.
« Last Edit: July 15, 2018, 06:39:54 PM by Shovel »

JakeP

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Re: Off-road Overheating Issues
« Reply #8 on: July 15, 2018, 08:32:49 PM »
Shovel - I know you aren't being a jerk, I've been around car forums enough to not get my feelings hurt. I've been a Honda guy my whole life, and this is my first time owning a 4x4 such as this, so these types of special situations are new to me. And let's me honest, this engine is a bit more complicated.

I don't believe it's the tires, most discussions I've read have said I can get away with a true 33 before having issues. I'm going to start on your list with the radiator service, cap, and thermostat. I think this is the best place to start. Like I said, I ONLY overheat under load when off-road. I drive the crap out of this car (it's my daily) and I don't think I've damaged the head gaskets because I do not have symptoms of it. I pulled my cap earlier and sure as shit it's original, Japanese writing and all. The seal is worn and cracked. Replacing first thing tomorrow. I hope the Mitsu dealer by me has a thermo in stock so I can get that knocked out then the rad service. I looked inside and it's got crusty build up all over.  But my fluid is crystal green and looks brand new.

Thanks for the write up, you've been very helpful. I'm going to start with these three and hopefully get it done before the weekend because I'm supposed to go to Aspen and then I can see if the issue has been fixed.

TOASTY

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Re: Off-road Overheating Issues
« Reply #9 on: July 15, 2018, 09:12:49 PM »



Shovel, best response ever.

RyanY

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Re: Off-road Overheating Issues
« Reply #10 on: July 16, 2018, 10:33:36 AM »
Shovel nailed it, as usual. The only point that I would add to his wonderfully thorough post is to be sure that your fan shroud is intact and correctly installed, both the main shroud and the small access cover on the bottom. A shroud that's broken or is missing the lower portion is compromising the efficiency of the cooling fan, which is what you're relying on for airflow through the radiator at slower vehicle speeds.

It's also good to note that the OEM metal radiator is far better quality and has more cooling capacity than the majority of the aftermarket radiators available. It's worth maintaining and repairing it instead of replacing it with some plastic/aluminum unit that won't cool as well and has a 5-7 year life expectancy.

JakeP

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Re: Off-road Overheating Issues
« Reply #11 on: July 16, 2018, 10:42:08 AM »
Update to thread. Turns out, one of the previous owners did have a cheapo 9.99 aftermarket thermo installed at some point. Good for daily driving but not sufficient for off-road. I was able to source an OEM one this morning locally, along with a new cap. Got these installed and dropping it off for the rad rod after lunch. Hoping these are my issues and will find out in Aspen this weekend.

This has been a great overall thread. I appreciate all the help and hope it can help others moving forward.

Shovel

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Re: Off-road Overheating Issues
« Reply #12 on: July 16, 2018, 12:12:44 PM »
10/10 would definitely read follow up to this next week!     :D

JakeP

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Re: Off-road Overheating Issues
« Reply #13 on: July 19, 2018, 08:19:06 AM »
Another update! I have had to cancel my trip to Aspen due to further issues with my cooling system. After replacing the rad cap and thermo, I developed a leaking radiator from two little pin holes at the top. Radiator shop said he can rebuild it next week and that I could drive it, but I am too concerned about the added pressures from being on a 4x4 road. As much as I would love to be stranded in the pristine Colorado basins I would like it more if I had a way out!

I also learned that my condenser fan does not operate, another check shovel mentioned. So I have that on order and should receive by next week. I think at this point I'll practically have a new cooling system in place and can't wait to put it to the test. Again, really happy this forum is here to help me troubleshoot and happy I can do the work myself! Who knows what this would cost taking to a shop.

RockyMountainMS

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Re: Off-road Overheating Issues
« Reply #14 on: July 20, 2018, 03:23:32 PM »
Another thing that might help for the off road cooling is either changing to an electric fan setup or adding one or two single fans to get more air to move through the radiator. I had the same issues with my Montero Sport. I changed everything I could think of short of the AC condenser/evap. Things I went through before switching to the electric fans are as follows:

  • Change timing belt/Water Pump
  • Change thermostat
  • Coolant Flush
  • Ensure fan clutch worked fine
  • Ensure the fan shroud was in tact
  • Ensure AC fan was working
  • Got the cooling system pressure tested for leaks in the system
  • Change the radiator
  • Change transmission fluid
  • Replace temperature sensors

Everything on this list was done and everything checked out. I would never overheat in any situation except for off roading. I think it in part has to do with the stock fan only being able to turn as fast as the engine since it is belt driven. The electric fan swap fixed my issue since it can run full tilt regardless of engine speed.

Even so, I know something is still wrong because the stock setup should work. In fact, I still get a little warm during serious off roading or on mountain highways with long steep inclines such as I-70 which you will likely encounter in Colorado. But I only start to overheat if the AC is on. Even then it only gets to about 3/4 of max temp. Still too hot IMO. If the AC is off, no overheating no matter what I am doing. With that said, I am changing every main component of my air conditioning system. My compressor siezes up peiodically and is only getting worse. So since I have to change that anyway, I am going to change the evaporator, dryer, and condensor at the same time since I will have to get in there and will have the system empty.

It might be worth doing the conversion just to get you on the road again. I spend tons of money, and time trying to figure mine out. At least I am off roading again doing the fan conversion. If you haven't seen my write-up, here is the link:

https://forum.adventuredrivendesign.com/index.php/topic,572.0.html

Obviously my write up is for the Montero Sport, but the concept is the same. You just have to get the right size fans for your radiator. Like Shovel said (and I didn't do), try to go OEM with the radiator. Another thing to consider is rigging your condenser fan up on a switch so you can control it or a setup like I did with my electric fan conversion where it comes on at the same time as the water pump.

I live in colorado, so if you want someone to tag along for safety reasons, let me know. I would be more than happy to go along. At least that way you have someone to get you out of a tough spot if something were to happen. There is a decent size Montero group here and we are really good about helping each other out!

Good Luck!

- Aaron
« Last Edit: July 20, 2018, 03:26:50 PM by RockyMountainMS »
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2004 Montero Sport LS
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