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Old 23rd July 2008, 21:06   #1
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Default Overheating problem in Jeep

Yesterday I was discussing the heating issue with GTO and he wondered whether I have a cowl around the fan. This is what I have and it looks rather far from the fan. Is this effective?
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Last edited by Samurai : 6th August 2008 at 12:55.
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Old 23rd July 2008, 21:21   #2
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Default Overheating problem in Jeep

The fan and shroud looks ok to me.
The presence and absence of a fan shroud makes a huge difference. I've learnt from experience.
I would suggest getting a proper size, high-flow electric fan which could be placed in front of the radiator. You could have it connected to a thermostat and also have a separate switch (for your fancy).
It could make a difference.

I've discussed this with my auto-electric expert mech and he suggested either the Ford Ikon's or the Palio's fan. Both are high speed ones.
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Old 23rd July 2008, 21:58   #3
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Quote:
Originally Posted by nitrous View Post
I would suggest getting a proper size, high-flow electric fan which could be placed in front of the radiator. You could have it connected to a thermostat and also have a separate switch (for your fancy).
If there is something wrong with his cooling system this may temporarily fix the symptoms but not the problem.

I think he needs to talk to an expert cooling guy and find out if there is a problem before he does anything else.

Samarai, you might enjoy this link:

HowStuffWorks "How Car Cooling Systems Work"
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Old 24th July 2008, 07:48   #4
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Quote:
Originally Posted by nitrous View Post
The fan and shroud looks ok to me.
The presence and absence of a fan shroud makes a huge difference. I've learnt from experience.
I would suggest getting a proper size, high-flow electric fan which could be placed in front of the radiator. You could have it connected to a thermostat and also have a separate switch (for your fancy).
It could make a difference.

I've discussed this with my auto-electric expert mech and he suggested either the Ford Ikon's or the Palio's fan. Both are high speed ones.
Sir, I beg to disagree on the above,

One could just make a good shroud to direct air flow into the radiator. The stock fanbelt system is good enough, UNLESS you have a overheating problem. And by overheating i mean over 110 deg C, not 80 or 90.

One adds an electric fan if one needs to be doubly sure that his jeep is not going to let him down, and for serious off roading.

Also, what nitrous claimed above, the palio and the ikon have 2 speed fans. Even a single speed fan of the M800 would suffice.

A separate switch could be used to start / stop the electric fan.

What I have done to my gypsy - I have a manual override on the electric fan. This means that i can use the electric fan in extreme situations or it will come on if the thermostat temperature exceeds a preset point or If I use the AC.


Quote:
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If there is something wrong with his cooling system this may temporarily fix the symptoms but not the problem.
What you say is 100% true, and the chances of not realising this is even higher!
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Old 24th July 2008, 09:30   #5
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Samurai suggest you get your radiator overhauled. Old cars invariably ran on plain water for coolant and this causes scale buildup. Sometimes blockages can also hamper the cooling effectiveness.

If this doesn't work get your water pump renewed. Chances are the impeller in your water pump may be the problem. If for any reason an undersized impeller was put (for lack of the right size being available) it retards the cooling effectiveness.

Last edited by DKG : 24th July 2008 at 09:32.
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Old 24th July 2008, 09:34   #6
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Quote:
Originally Posted by DKG View Post
Samurai suggest you get your radiator overhauled. Old cars invariably ran on plain water for coolant and this causes scale buildup. Sometimes blockages can also hamper the cooling effectiveness.
I did replace the radiator core with a new one because of all the leaking problem.

Quote:
Originally Posted by DKG View Post
If this doesn't work get your water pump renewed. Chances are the impeller in your water pump may be the problem. If for any reason an undersized impeller was put (for lack of the right size being available) it retards the cooling effectiveness.
Hmm, then my next target is water pump. Also I'll try to replace the square fan cowl with a circular one. Hopefully that should make some difference.
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Old 24th July 2008, 09:40   #7
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Samurai while you are at it get some descaling agent and pour it in and keep flushing the system out. Scale buildup around cylinders also causes this problem.

Also check if its the right fan for the model. Also please check the distance of the fan from the radiator. If there's too big a gap then too cooling effectiveness goes down. Sometimes with different engines being slotted into these Jeeps not enough care is taken to ensure the radiator is positioned optimally. Which is why the shrouds become important.

Last edited by DKG : 24th July 2008 at 09:42.
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Old 24th July 2008, 10:27   #8
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Samurai,

Your cowl looks pretty good. You need to visit a competent garage and check the following checked:

1. Condition and size of current fan / blades

2. Radiator

3. Water Pump.

Don't go in for the electric fan, no need to complicate the Jeep. If my CJ works perfectly with the air-con on, there isn't a reason for yours not to. Even though you have gotten the radiator core changed, the quality & flow counts too. I am still not convinced that your radiator is working efficiently enough. Have you used any branded parts? If you wish, I could have Lawrence radiators custom-build a high-flow large size radiator for you. My CJ is wearing an example from Lawrence and I can tell you, they are the best in the business. First check the state of your water pump and if that is working alright, then I'd suggest a radiator upgrade. Alongwith the water pump, also get your radiator cap checked up.

Lets get to the bottom of this problem.
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Old 24th July 2008, 11:26   #9
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I agree. Mine was just an "mseal" solution to the problem.
In the path to identifying the culprit, the next stop is water pump.
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Old 24th July 2008, 13:58   #10
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No, before the water pump is the raditor cap. Use the correct cap with the rated pressure.

Also, check if your temp gauge is accurate enough!

And if you do not have a pressurised cooling system, get it done after the radiator stuff. Then comes the water pump bearings
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Old 24th July 2008, 23:16   #11
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Quote:
Originally Posted by tsk1979 View Post
20W40 does not mean its the range of temperature.
The upper number is called the viscosity of engine oil at 100 degrees .
So a 20W50 oil will be more viscous at 100 degree C as compared to 20W40 or 10W40 etc.,
The 10W, 5W, 0W oils means low temperature pumping.
0W oil is not tested at 0 degree C, but at -35 Degree C
5W is tested at -30C
10W is tested at -25C
So 10W40 does not mean that oil can be used between 10 degree and 40 degrees, because engine oil temperature often touches 80 degree+

Motor oil viscosity - Castrol Motor Oil
Motor oil - Wikipedia, the free encyclopedia
You will see that 20W50 oil can be used for temperatures above 20F
32F is 0 degree C, i.e. the freezing point of water
5W40 can be used for temp < 0 F
Please don't go by what is given in the wiki link. Oil being tested at some temperature does not mean the rating implies that temp.

From the castrol link you posted ->
"This makes multigrades an easy and popular year-round choice for drivers who experience hot summers and harsh winters. Multigrades are easily recognized by the dual viscosity rating (i.e. 10W-30 where the 10W is the low temperature or winter designation and the 30 is the high temperature designation). It is the motor oil viscosity modifier additive that produces a thickening effect at high temperatures but is dormant at low temperatures."

You yourself says that 20W50 can be used at 20 deg F, I had mistakenly taken it as 20 deg C, mea culpa.

To simplify matters I quote ->
HowStuffWorks "What does the weight mean on a can of motor oil?"

"At cold temperatures, the polymers are coiled up and allow the oil to flow as their low numbers indicate. As the oil warms up, the polymers begin to unwind into long chains that prevent the oil from thinning as much as it normally would. The result is that at 100 degrees C, the oil has thinned only as much as the higher viscosity number indicates. Another way of looking at multi-vis oils is to think of a 20W-50 as a 20 weight oil that will not thin more than a 50 weight would when hot."

Hope that clears matters.
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Old 25th July 2008, 08:01   #12
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Quote:
Originally Posted by nitrous View Post
.... the next stop is water pump.
Wait wait wait.

Samu, there is one more think you can check before going through the trouble of checking the water pump.

It is possible that your thermostat (the mechanical device not the sensor) is :
1. Not opening at the right temperature
2. Not opening wide enough
3. Not opening at all

Please do get that checked out. (You could even do it yourself).

An explanation of the thermostat and how to test it yourself is mentioned in my post here : http://www.team-bhp.com/forum/246847-post12.html

cya
R

ps - i searched in this thread for thermostat just to make sure you hadnt already checked it, but found nothing.

ps 2 - i cant seem to see the thermostat housing in the enginebay pics ?!

Last edited by Rehaan : 25th July 2008 at 08:05.
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Old 25th July 2008, 10:47   #13
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@Rehaan - why should a jeep have a thermostat?

Most new generation cars' cooling systems (the fan actually) works only when temperature goes above a certain limit. The limit is set in the thermostat.

The jeep, AFAICT, uses plain old cooling system. The fan, (again) AFAIK, always runs when the engine is running. The radiator / coolant fan on most modern cars start to run only when temperature goes above the threshold. Hence, there would not be a thermostat in a jeep's cooling system. Unless this jeep's cooling system was modified to included a thermostat.

Additionally, in old generation cooling systems, water is simply circulated, but not at high pressure as seen in most modern vehicles.

Did I read somewhere above that this particular jeep uses coolant in water? And are not coolants used to increase specific heat of water (hence absorb more heat at same temperature)? My common sense tells me that this also requires better heat dissipation at the radiator end of the cooling system. Was adding coolant accompanied by modifications to water pump and circulations to enable high pressure circulation? If not, I suggest to start trouble shooting by NOT using coolant in water.

PS:- I am not suggesting a solution, but some pointers to trouble shooting.

2nd edit- saw that link to "what a thermostat really is" link by Rehaan. If that is what a thermostat does, what is the device whch switches on the fan called?

Last edited by BaCkSeAtDrIVeR : 25th July 2008 at 10:57. Reason: Added the ps and corrected the spilling mixtake in the mod's name.
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Old 25th July 2008, 10:54   #14
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samu: what is your exact problem which you are referring to by "overheating"?
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Old 25th July 2008, 11:06   #15
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Quote:
Originally Posted by backseatdriver
@Rehaan - why should a jeep have a thermostat?

Most new generation cars' cooling systems (the fan actually) works only when temperature goes above a certain limit. The limit is set in the thermostat.

The jeep, AFAICT, uses plain old cooling system. The fan, (again) AFAIK, always runs when the engine is running. The radiator / coolant fan on most modern cars start to run only when temperature goes above the threshold. Hence, there would not be a thermostat in a jeep's cooling system. Unless this jeep's cooling system was modified to included a thermostat.
Rehaan was explaining about the Thermostat valve. not the thermostat controlled radiator fan(which isn't present in samurai's jeep).

This thermostat valve is present to warm up an engine fast(so as to reduce engine wear). When the engine is cold, the thermostat valve is fully closed,so that the water in the water jackets of the engine circulate within the engine and get warm fast. Once,the engine gets warm, the thermostat valve now opens to let the coolant pass through the radiator,thus regular engine->radiator->engine coolant flow happens.
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