Jimny cooling system issues

[Mud_Muncher]

Had a few issues with the cooling system on my Jim. First off I put a hole in the Rad and steam came pouring out. I replaced it and the fan which was missing fins from scorching the rad.

It still overheated on hot days. I did a coolant system flush then pulled the rad out again and took the water pump off. I noticed there was still green coolant in around the pump after flushing the system with clean water while the engine was running.

Does this mean that the thermostat is faulty causing the pump system not to open? The fins on the water pump seem to be spinning fine and look ok. (both parts are being replaced either way just as a matter of course)

The fins on the fan have scorched the rad again. Can you trim the fan up a little of the damaged corners or maybe a little more? What would cause the fan to be sucked into the rad like that?

Thanks for the help!

[hobzees4wdshop]

When you go through deep bogholes....similar to this:



Water will rise up into the engine bay and the fan will start to hit the water causing it to torque up and pull itself towards the radiator like a boat propellor.

[Mud_Muncher]

The question still remains 'how do I drive from the passengers seat'?

[spamwell]

When you go through deep bogholes....similar to this:



Water will rise up into the engine bay and the fan will start to hit the water causing it to torque up and pull itself towards the radiator like a boat propellor.

no it won't because they have a clutch fan if it is a g13bb so when it hits water it stops instead of causing suction.

[Mud_Muncher]

Yes spamwell,

It is a M13a which has the viscous coupling fan.

Got me stumped? Maybe the fan doesn't slow down straight away?!?

[hobzees4wdshop]

no it won't because they have a clutch fan if it is a g13bb so when it hits water it stops instead of causing suction.

Well if its not that, then whats causing the damaged radiator fins on the engine side even if it is a clutch fan....got me stumped

[GRPABT1]

I'm with hobzee on this one, you may be able to get away with a decent thermo fan which you can switch off when crossing deep water.

[zookimal]

Haven't done any emergency stops recently? Mounts haven't flexed and the engine shifted forward?

Probably unlikely in a Jimny but I have seen it happen in other cars.

[greg]

It is a M13a which has the viscous coupling fan.

I'm guessing the viscous liquid is 'thick' enough to keep driving against the resistance of some of the water.

I've never tried stopping the fan on my g13bb jimny engine once it gets going to i couldn't really confirm just how much resistance it would take to stop them though.

[MART]

Your question about trimming up the fan blades , I would replace the fan if it is damaged because the most common cause of overheating is damaged fan blades not drawing enough air through radiator because the fan blades are to far from the shroud , everybody tends to blame other items like the water pump , thermostat , but if you have a standard setup you shouldn't overheat , Cheers Paul.

[robsjimny]

With the m13a the a/c fan will kick in when too hot also.

[scooby_74]

Did a quick check should be able to just slide your hand between fan and rad, if not poss rad supports are bent and rad is too close to fan, both bb and m series engines will turn on the electric fan if the computer thinks its too hot should also turn a/c off at the same time.
Was the rad that you replaced new, if not did you have it serviced, if they block in the middle cores the viscous fan wont work.
If you want to check your viscous fan hold the fan and get some one to start the engine, hold it for 2 mins and then let it go, should draw realy hard for a few seconds as the silicone in it would have expanded from being stalled and engage the hub.

[Mud_Muncher]

Thanks everyone for the help, i will check it out tonight.

Scooby, thanks for checking those things outs for me. Will take some balls to hold the fan while starting the engine!

[Mud_Muncher]

Got it all back together with top quality coolant (red nulon) and a new water pump. Still starting to over heat sitting in the shed on a warmish night (25c). The water in the rad is boiling which i assume means that the water is being pumped around the engine correctly.

I think i will have to bight the bullet and buy yet another rad, I think the scoring has damaged it to the point of making it useless. Do companies still re-core radiators at a much cheaper price then buying a completely new one? Dank had this done a few years back, but I couldn't find a place that would do it.

[atari4x4]

have you checked or replaced the thermostat?

[gman79au]

Mud MUncher I've been down this road with my 01 jimny, I found the viscous clutch was faulty, causing over heating swaped fan and clutch from a g13bb engine and all is good, fan is slightly different but still does the job, found this by driving the Jimny with the fan locked to the clutch with cable ties, a good fan will take a fair bit to stop with hand while idling a stuffed fan you will stop easily don't be scared,

I also drove the fan into the radiator while off road last year replaced both engine mounts and problem solved, old mounts look ok but they must sag with lots of off road use cause it does hit any more, I found it a bit more expensive to have to radiator fitted with a brass core instead of alum but It now can be repaired if I get another hole.

when the original setup works, it works well fitting thermo fans etc is just a band aid.