flow kooler/Robert Shaw thermostat

Pelican said:

What is involved in "DIY" porting on the stat housing?

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I basically took a die grinder and attempted to make my thermostat housing look like this

http://www.hesco.us/products/9388/r...igh-flow-thermostat-housing-hfth#.U1L5c1RdUZo

or in other words, I knocked the corner off of where the coolant passage from the hose meets the thermostat area. There's tons of meat in that area and it's a pretty obvious restriction to flow.

Had occasion to run out and help someone with a noise/brake issue, so got to see how it's working out on the road now. Temps fluctuate from 197ish to a high of 206 sitting still at a light, it's about 70F today, so I'm feeling better now. Before it was getting up to 215 and rising and that's when I'd reach down and turn on the A/C to force the fan on. With a new clutch I think I'll be ready for summer.

Thanks.

rockclimber said:

Why is your engine running at 195 and not 210?

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I do not know if there is something wrong with N8N_99xj engine or the cooling system but my XJ stays below the 210 degrees mark when on the highway and have been that way for many years. Typically is read between 198 and 204 degrees on the Scangage an below the 210 mark on the dash gage. in stop and go traffic both gauges will get up to 214 degrees before the e-fan come on and pull it back down below the 210 mark. It have been that way since the dual e-fans were installed in 2004.

His XJ have a mechanical fan. If the cooling system is in good working order then it is possible to have the engine temperature remain at the thermostat temperature. If the engine temperature remains below that of the thermostat then that would be cause for concern.

Fan clutches do not last forever! They are relatively inexpensive and will cure the low speed temp "creep" most of the time. Low speed rise is directly related to improper airflow. My 99 with an entirely new cooling system never gets above 195.

N8N_99xj said:

I basically took a die grinder and attempted to make my thermostat housing look like this

http://www.hesco.us/products/9388/r...igh-flow-thermostat-housing-hfth#.U1L5c1RdUZo

or in other words, I knocked the corner off of where the coolant passage from the hose meets the thermostat area. There's tons of meat in that area and it's a pretty obvious restriction to flow.

Had occasion to run out and help someone with a noise/brake issue, so got to see how it's working out on the road now. Temps fluctuate from 197ish to a high of 206 sitting still at a light, it's about 70F today, so I'm feeling better now. Before it was getting up to 215 and rising and that's when I'd reach down and turn on the A/C to force the fan on. With a new clutch I think I'll be ready for summer.

Click to expand...

Is this all by looking at the gauge? Or was temp verified with an IR gun?
An IR gun helped me determine that my temp gauge reads 10-12F higher than what actual coolant temp is.

I also recommend using some "Water Wetter"

By looking at the gauge and also reading a Scangauge.

I got a new Hayden 2737 fan clutch (listed for 2.5; supposedly more aggressive than the 4.0 one) installed it yesterday, holy hell, that sucka is loud. Either it's REALLY more aggressive than the 4.0, or my old one was all wore out. No issues with fitment and I didn't have to remove anything other than the clutch and two little screws for the fan shroud. It was only about 70 degrees yesterday but I sat in front of the post office idling waiting for my friend for a good 15 minutes and now temps fluctuate between about 197 and 205 never rising higher, fan seems to keep it under control and the fluctuation is simply due to the thermostat cycling, so I'm probably not going to get tighter control than that.

Dammit! Found this thread after the stat on my "new" XJ stuck open on the way to work today and I can't remember what I ordered, and I don't see it here. Is it the 330-195 (AMC size) or 370-195 (MoPar size)? I want to say it was the 330 but I don't 100% trust my memory.

I *could* just pull the known good thermo out of the '99 before selling it but that sounds excessively cheap, although I did port that housing too...

Edit: after searching my email to no avail, I found that I apparently did order a 330-195 direct from FK back in 2014, so that must be it. Damn $21 though!