Originally Posted by mtbtim

I absolutely agree with what you said. The problem with the analog coolant gauge is it's a poor indicator of the engine temp you're running at. The needle doesn't react until your engine is really hot. At what temp the needle actually starts to rise, I don't know, but I've gotten to 215 and the needle was still in the same location it would be if you were at the normal operating temp of high 180's to low 190's. In my opinion, a 30+ degree change with no needle movement is problematic. This is why I like using a secondary means to monitor engine temp. At first I used the phone app Torque Pro but I've since moved to using a Scan Gauge in each of my 3rd Gens.

I don't glance at my scan gauge constantly while driving, so if I burst a coolant hose, I still might not catch it in time before major engine damaged occurred. I mostly closely monitor it when I'm driving in adverse conditions. The ambient temp is high, 90's and above and I'm driving loaded down with gear and/or driving up sustained grades. This is the time I'm also closely monitoring my auto trans temp. Knowledge is power in these circumstances and I've more than once on trips pulled over to the side of the road and idled my engine until my engine and trans temp have gone down. When I'm creeping up on a 210 engine temp or a 220-230 trans temp, that's when I start to consider pulling off the road and giving my rig a break. I'd rather it take longer to get to my destination than burning up my engine or trans and then never getting to my destination. That day I was driving in Nevada and the ambient temp was around 210-215, I saw carnage all over the highway. There were passenger cars and trucks pulled off with what clearly looked like to me they overheated their vehicle.

I always highly suggest that people use an alternative means to monitor important things like Engine Temp, Auto Trans Temp and Charging Volts.

Originally Posted by brillo_76

I didn't know the ambient temp in Nevada got to 210 to 215. I thought that area got around 110 to 115.... ;-)

I have had my 3rd gen up to 3/4 on standard dash gauge. I can understand the gauge may not be super accurate. But, I suspect the red zone on that gauge is the danger zone damage zone as per engineers would make it that way. :-)

I believe the variant without the gauge moment is on purpose. Owners would be complaining of the temp gauge would fluctuate wildly in normal operation. So my theory, is they have zone of no movement under the normal range operation.

I can understand, folks wanting to monitor things closely. I can agree with that if they want to. :-) I just check my fluid levels. Do maintenance and hope for best. Served me well since the 80s trucks. :-)

I do wish they would have options of full gauges. Like a built in android tablet that can just have a mode...

Originally Posted by Endlessblockades

I wouldn't trust the dash temp gauge, personally. Mine was happily pegged in the middle as I took my rig on a sustained desert 'mountain' climb (Little Berdoo Canyon). I was shocked to see coolant temps go to 249 degrees on the Ultra gauge I had installed a few days before. The dash gauge wasn't moving any higher and I later heard that 250 degrees sets off a Temp light which seems rather extreme. There is some debate about which temp sensor the OBDII taps, but I stopped to cool down for 30 mins. Kept it in 4Lo the rest of the day but was still seeing 220s. Replaced the likely original 200k radiator with an OEM (wasn't aware of these options), new TStat at 6pm (it was at 12) a Tru-cool inline trans cooler and I now see 188 on the highway and 200 at max offroad stress. I view my dash temp gauge with the same suspicion I have for my fuel gauge - not to be fully trusted.

Originally Posted by mtbtim

The OBDII taps into the temp sensor at the front of the intake manifold since it's the one that communicates with the ECU. The temp sensor at the back of the intake manifold is the one that communicates with the engine coolant gauge on the dash cluster.

Yep, no way I would rely solely on the analog coolant temp gauge. This is especially important for anyone that drives in adverse conditions like you were doing in the desert. I think you got lucky. I would have pulled off to let the engine cool down WAYYYY sooner than that. I think you dodged a bullet not doing any engine damage. 250 is HOT for these engines.

Originally Posted by phattyduck

There's no engine temperature light.

Originally Posted by 2TH4IST

Been running this rad for a few years now. It's super nice. Also foam tape the fan shroud to make the system as efficient as possible.

Originally Posted by 2TH4IST

Been running this rad for a few years now. It's super nice. Also foam tape the fan shroud to make the system as efficient as possible.

Originally Posted by 2TH4IST

@Endlessblockades I used your run of the mill foam weatherstripping from home depot. I think it was 3/4" thick for the top and bottom of the shroud and 3/8 or 1/4 for the left and right sides (it's been so long I don't remember the sizes, i just eyeballed the sizes and went out and bought what i needed). I did attach the foam to the shroud not the radiator. I also left a 1/4 inch gap at the end of bottom foam on one side so it will allow water to drain out, from rain and water crossings. Zero issues with the heat from the rad regarding affecting the foam.

@brillo_76 100% better then the "oem" denso's. Nothing to worry about on the koyo vs oem. I use oem loosely with these denso's. The denso the koyo replaced the top plastic tank was out of spec for the rad cap. The 2nd sealing surface was about 1mm to low and would not let my cooling system build pressure. Found this out after going through 4 radiator caps. Only downside to the koyo is that it doesn't have the internal trans cooler. So there will be an extra cost.

Either way I don't regret the koyo at all. I know it's reliable, the fit is always amazing (I have a few koyo's in my cars). Also I do believe (I could be wrong) the koyo is a triple pass radiator (down up down or up down up), which is amazing at the price point the koyo is at. It would be even better if someone made a triple pass cross flow copper radiator, but I'd guess it would be in the 1k to 2k price range lol.