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The problem with modifying your vehicle.

23 Aug

I guess everyone has made modifications to your car, truck, or SUV at some point.  How many the cost and difficulty vary widely I am sure.  I remember the good old days when putting “mags” or any non OEM wheel was the extend of my modifications.  My first car was a 1973 Pontiac Ventura.  It was the same body as the Nova, just different grill and tail lights.

Wheels, tires, traction bars then a 327 small block.  I just didn’t have the money back then to do all the things that would have made it a truly amazing vehicle.  What I had was fun though.  I don’t recall any issue that I had with that car that I couldn’t solve.  Fast forward several years, and vehicles, and I’m modifying our Jeep Cherokee.

I’ve had a 4×4 truck before, and after a lift, much larger tires and wheels, my modifications were pretty much complete.  I had no idea there was so much more that could be done.  Primarily because that was in the days before the Internet and information wasn’t nearly as easy to obtain.  I started with the Jeep like I did the truck.  A lift and larger wheels and tires.  Shortly after doing that I found that I had a problem, well first a little history on this problem.

My wife and I decided on and purchased a 1998 Jeep Cherokee from a local dealer in 1998.  About 2 years later I was driving home from work and to my surprise I noticed the temp gauge showed a over heat situation.  I was on I-10 and I’m sure I was doing 80 mph or so.  I got off the freeway and parked letting it cool down.  After 1 maybe 2 more stops I made it home.

I took the Jeep to a local shop to have the problem diagnosed.  It was a bad water pump.  The plastic fins on the factory water pump were all gone!  Kind of hard for the pump to move water through the system.  The shop claimed that the head had warped due to the over heat.  So the head was removed and sent off to be milled.  Head replaced, water pump and she was back in running shape.

About 3 months after this major problem the radiator started to leak.  I took the Jeep to a local radiator shop and they told me since the radiator was a mix of metal and plastic it could not be repaired and should be replaced.  I was shocked to find out that anyone in their right mind would put plastic on a radiator!  They had a replacement all metal radiator which they quickly installed, $225 later I was on my way.

Soon I started to see a pattern.  After a few months of running at 210 degrees the coolant temp would rise.  I would check the coolant level, find it was low and add coolant.  Apparently I had a small leak somewhere but it wasn’t apparent.  Oh it seemed that anywhere from a year to two years I would have to replace the water pump.  That really sucked!

Hurricane Rita threatened us and I decided to lift and build up the Jeep so we would be able to evacuate.  It quickly became a hobby.  After lifting and putting the larger tires on the Jeep I noticed that I had added a new problem, but perhaps one that had been there all along.  My cooling system would start getting hotter on the highway, but perform fine on the slower surface streets.  Based on my past experience I knew that a radiator with an additional row would make a huge difference.  I purchased and installed a 3 core all metal radiator.  I took the 2 core to a radiator shop and had it checked and repaired for a backup.  Sure enough there was a small leak.

To my shock the 3 core radiator did NOT solve the running hot issue.  I may not have worried about this problem but after driving on the highway I could literally SMELL the hot from the engine.  This isn’t good for the engine, or the transmission.  I needed to resolve this issue.  Researching the problem on the Internet I found that the Jeep Cherokee’s all had a cooling system issue, it was a problem with the design.  The radiator is long and narrow.  This makes it difficult to place a large fan that moves a lot of air through the radiator and cools the engine coolant.

Jeep’s solution was to place a mechanical fan and an electric fan.  The electric fan would only come on when the coolant temp reached 220 degrees (approx.) or when the A/C was on.  There is a A/C condenser, which looks much like a radiator, then the radiator.  So when the A/C is on vast amounts of heat are pushed to the condenser, cooled by the passing air.  Some of this heat gets transferred to the radiator.  Also the radiator is used to regulate the temp of the transmission fluid.  It heats the transmission fluid when it is cold out, and cools it when it is hot.  One theory for the coolant running hot was with the larger tires the transmission was having to do more work, so the addition of a transmission cooler may help.

I added a 13,000 BTU transmission cooler, no change.

I added a HD fan clutch, high flow thermostat, high flow thermostat housing.  A high flow water pump.  All new hoses.  The coolant was a beautiful green, 50/50 mix.  Still runs hot on the highway.  I had been told repeatedly that at highway speeds your fans are not needed.  Well since I have hooked up a electric fan bypass I was able to turn off my A/C and leave the electric fan running.  During a highway speeds test the coolant temp returned to near normal, and even in the afternoon when the Summer heating was at its worse the cooling system was running much cooler.

So the fan does make a difference at highway speeds!  With this new knowledge I found and ordered a 12″ fan for $89 shipped.  This 12″ electric fan will replace the factory efan at 530 CFM (Cubic Feet per Minute) and the replacement I ordered is a 1050 CFM.  So that is nearly double the air flow for the driver’s side of the Jeep.  I also ordered from eBay a Ford Taurus dual speed fan.  4500/2500 CFM.  2950 CFM is recommended for towing and long steep inclines.

So once you get started modifying things you may wind up with somewhat of a money sucking black hole!  One of the truly amazing things about the Internet is to help the next guy with the same problem go directly to the problem’s solution.  Sad thing is I was considering replacement fan way back and the beginning of this problem.





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