[JeepJeffW]

Get the flush kit from Prestone if you're going to go that route. It has a diverter that fits in the radiator cap opening and guides the flushed fluid away from the vehicle and, in my case, into a five gallon pail. When you cut the heater hose running along the engine (its the inlet to the heater core) and install the garden hose you will get a complete flush for as long as you want.

On thing I do is add the chemical in the flush kit to the old coolant BEFORE I flush it, run the engine a little to get it dispersed throughout the system, and the let it sit for about 15 minutes before doing the actual flush. While the chemical is doing its thing I kill the time by cutting the heater hose, installing the "T" connector and getting everything ready for the actual flush.

Lastly, after I finish the flush I disconnect both hoses from the heater core and flush it again in both directions, starting with the inlet (top on mine) to insure it is clean.

Regarding the thermostat, I use the 190 (actually a 195 if I remember correctly).

[erickpl]

I believe stock radiator caps are 190 degrees. But I'm certain somebody will correct me if I'm wrong.

[C2U5H]

Originally Posted by JeepJeffW

Get the flush kit from Prestone if you're going to go that route. It has a diverter that fits in the radiator cap opening and guides the flushed fluid away from the vehicle and, in my case, into a five gallon pail. When you cut the heater hose running along the engine (its the inlet to the heater core) and install the garden hose you will get a complete flush for as long as you want.

On thing I do is add the chemical in the flush kit to the old coolant BEFORE I flush it, run the engine a little to get it dispersed throughout the system, and the let it sit for about 15 minutes before doing the actual flush. While the chemical is doing its thing I kill the time by cutting the heater hose, installing the "T" connector and getting everything ready for the actual flush.

Lastly, after I finish the flush I disconnect both hoses from the heater core and flush it again in both directions, starting with the inlet (top on mine) to insure it is clean.

Regarding the thermostat, I use the 190 (actually a 195 if I remember correctly).

Originally Posted by erickpl

I believe stock radiator caps are 190 degrees. But I'm certain somebody will correct me if I'm wrong.

Just a double check bumpity-bump.

Get the 190*F thermostat, correct? I've read about the "low temp" thermostats (180*F) and concluded it's not right for the 4.0L ... it just runs hot. Nature of the beast.

[Bigbob]

Originally Posted by erickpl

I believe stock radiator caps are 190 degrees. But I'm certain somebody will correct me if I'm wrong.

I have a variable temperature radiator cap. It normally stays pretty close to the same temperature as the actual radiator. It can vary a couple degrees depending on the outside air temperature blowing in under the hood.

I use a stock thermostat which I believe is higher than 190. The radiator cap stays pretty close to whatever temp the thermostat is as well.

Sorry, couldn't resist!

[hscrugby]

Originally Posted by Bigbob

I have a variable temperature radiator cap. It normally stays pretty close to the same temperature as the actual radiator. It can vary a couple degrees depending on the outside air temperature blowing in under the hood.

I use a stock thermostat which I believe is higher than 190. The radiator cap stays pretty close to whatever temp the thermostat is as well.

Sorry, couldn't resist!

Nice.
Yea, OE is 190/192 degree for the tstat. If you put a cooler one on there, your engine might not heat up enough to get out of "warmup" mode.
In the winter, it definitely won't.

[jakecarder]

my 98 has a tensioner. its on the right down kinda low. you have to loosen the pully on it and then theres a long bolt you adjust and it loosens the belt

[erickpl]

Well, here is my saga about this.

I determined my t-stat was stuck open, so I did the flush/clean with the Prestone flush kit and their cleaner. Foamed up good and really cleaned out my system well. Did the water inline with the kit and backflushed it. Looked at the hoses and all look REALLY good.

Filled up after the water rinse out to make sure it was all clean and water came POURING out of my water pump. DANGIT!

Forget weep hole. It was Niagara Falls! So it was off to Adv Auto for a new pump (31.00). I got another t-stat gasket in case it was my botching that part of it. Swapped the t-stat gasket, and put on the water pump (my 2.5L is actually a reverse flow model as noted by the "R" on the impeller). Installed that, and filled everything up, let it run, and temps working the way they were supposed to. Drove it the next day and within 2 miles of my house it was at the normal operating temps. VERY happy about that.

I noticed my factory pump was tough to turn once I had it off. The new one spun MUCH easier and I swear the engine feels like it gets up to speed a LOT faster than before. I found myself going 55 in an area I could only be at 45 before. Maybe it is a placebo effect, but the engine feels better and feels like it responds better.

I think cleaning out the system, degunked the pump to the point that the weep hole was exposed and showed the seal as failed. Now I have peace of mind that the system is clean, and I have a good t-stat and water pump.

I thought the pump would be a PITA to swap, but it really wasn't that bad. Remove fan shroud, fan, and belt, and it is EASY to swap out. Taking things apart the first time, I took about 30 minutes to make sure I noted which bolts went where. Putting it back in took about 10 minutes, and 5 of that was getting the gasket sealant on the pump and engine.

For only 31.00 it was not expensive either!