New purchase '92 L300, temp gauge not working?

[ryan.vande]

Hi everyone,

I recently just bought an L300 super exceed turbo diesel. I was driving around today and noticed that the factory engine coolant temperature gauge in the dashboard was always climbing to max within a few minutes of starting it up. There's an after-market pyrometer also installed which sits pretty consistently at between 4-600 F when driving flat, a little higher when going up big hills etc. I was advised to not to push it passed 11-1200 F to help save the engine, and want to keep everything in good shape so I've been following that advice.

The engine coolant gauge is kind of freaking me out, because I know that's not a good sign. But, the temp on the pyrometer seems fine, and the engine runs super smoothly (no coughing or sputtering or smoke). I've been reading about how the factory engine coolant gauge can be unreliable...does the pyrometer on its own give me a reliable way to gauge temperature? I'd hate to end up ruining it before I get to even enjoy it.

Any advice anyone can provide would be a huge help. I'm excited to join the delica club!

[thedjjack]

check it asap with a working mechanical gauge

it most likely is a bad sender unit on the gauge

But it could also be a stuck thermostat (or other cooling issue with coolant movement)

DO NOT DRIVE UNTIL YOU ARE SURE....EGT are just the temperature of the exhaust gas and will not show the engine temperature

If it is the thermostat I would go OEM on new, and a good time to do the cooling system if empty or add a block heater and change hoses...

[Rattlenbang]

I don't think you can count on EGT temps to reveal coolant temperature. Generally, if you have some experience with engines, it's not too hard to tell hot from too hot. When it gets TOO hot, everything smells hot, the engine compartment feels way too warm, and the hoses are painful to touch. You will also find a lot of coolant pushing out into the reservoir, and then onto the ground. Is the reservoir filled to the brim? Is the rad low? is the air coming out of the heaters extremely hot? It is possible that the gauge or sender is off, but I would look very carefully at cooling system for plugged rad, coolant level, and whether or not you have a cracked head (is the cooling system overpressurizing?)

[glenn]

I had the same exact thing happen to me. It was on a dark unpleasant stretch of road in front of the old asylum in Coquitlam, and I had my under 10 year olds with me, I looked down and the temperature had spiked to H. I pulled over, let it cool down for a while. When I started it again, the temp climbed back up. I quickly realised after this, that the van was running totally normally, and it must be the sensor. I took it real easy back home - next day confirmed it was the sensor.

[Firesong]

I agree. Stuck thermostat or sensor.

[joshh]

I also agree. I have been plagued with bad temp sender unit before, on multiple vehicles. both were on 20+ year old JDM vehicles.

and ill also vouch for checking the radiator for calcification. mine was severly plugged when I got it, as most are from japan. its always good for preventative maintenence to change the rad(or have it cleaned out/re cored), thermostat, hoses, and temp sensor in one shot. makes for peace of mind.