I am not an expert on thermostats by any means – I usually follow the general advice I am able to gather from this forum. I think the 190 I am running was purchased from Extinct when I bought my inline kit a couple of years ago.

 

That Amazon thermostat would work fine, if not ideal. The thermostats we supply are all high flow thermostats vs the Amazon one is standard flow. The high flow probably is better in high temperature/load conditions although to be honest I never really tested the standard ones at high load. Also, everyone please be aware, you will have a cold start temperature spike before the thermostat opens for the first time if you leave the jiggle pin in, jiggle pins are designed let air pass through the thermostat so the hose does not collapse on cooldown, they are not designed to allow cooland to flow. In fact if you look at them the flat disc portion of the jiggle pin is on the engine side of the flow, so when the engine is started cold the flow/pressure forces the disc against the hole basically sealing (not a perfect seal) off flow. The ones from us do not have a jiggle pin so that the flow can circulate past the thermostat and open at the desired temperature with no spike due to the delay from waiting for the coolant in the hose to heat up.

 

Very helpful, that seems to be my fix, will try that this weekend. thanks

 

@Extinct Do you have model number for the 190 hi-flow, I need to swap out the Disco is staying pretty cold right now.

 

PM'd. For others who may find this, the high flow Motorad thermostats we use are not standard for any oem vehicles and you will likely not find them in stock at any autoparts store (I never have). Most OEM replacements do not have the pre-punched hole that ours do but you can use any standard small block chevy 1955-1987 thermostat, just drill a 1/8" bleed hole. We keep them in stock of course but sometimes they are available from Amazon, less common outside of the US so if you are international it is a good idea to order some spares. The shipping cost alone to international locations is more than the cost of the thermostat element (sorry Canucks, we would both benefit if the shipping cost was lower, I had to send a customer a $60 refund due to UPS gouging him on a customs charge )

 

@Extinct thanks for the PM

 

Seems to have fixed the low temp error, thanks for the advice. just broke the pin off w two pair of pliers.

 

I had updated the entire coolant system (new water pump, reservoir, all hoses, Extinct in-line) 2 months ago and since then, the girlfriend had the truck so I wasn't really able to monitor temps. Just driving around town that one day, the ScanGauge would read 190 and by then the 180 thermostat would open and temps drop. Maybe we got to 204.

Yesterday, driving down to Albuquerque and then back to Santa Fe, hot day at 95 degrees outside, the temp got up to 238 and stayed there (quick peak at 242 degrees) and it didn't drop - could the thermostat be "stuck?" or did everything just get that hot?

I ended up opening windows and running the heater full heat and dropped the temps down to 220 for the hour drive home.

Thoughts on diagnosis procedure? The one hose off the inline does have a tight bend, but it's not kinked...

 

Oh, that’s very hot! 242*! That’s very close to where you would cause damage. Good that you turned the heater on. Could be various things, but the first thing I’d try is a new thermostat. And while you’re at it, cut the hose shorter to get rid of the slight kink. My $.02 worth.

 

Yes, much too hot! That hot on the highway suggest you have a plugged radiator although it could be a failed thermostat but unlikely. First step is to pull the thermostat element out of the housing completely because at 95° ambient temperatures you don't need any thermostat. Put it back together with no thermostat element in the housing and run it and see if it still gets hot, my guess is it will and that tells me you have a plugged radiator