coolant temp/gauge question.

[piperpilot26]

hello all,

while driving the jetta around today I notice that when fully warm the temp gauge sits at exactly the halfway point, right over the temp warning light. While under a load or going up hill the temp gauge will move slightly higher, but not past the warning light and it hasn't overheated at all. My question is, is this where its supposed to be reading when fully warm? also I noticed that the cooling fan hasn't been kicking on at all. At first it wouldn't even kick on even with the A/C on, but after cleaning some connections it now works. Maybe I should try cleaning the temp sensor connections?

[bscutt]

Mine typically reads mid scale or very slightly above. In cold weather it gets a little hotter, probably because the radiator and thermostat is in a colder location than the sensor, but it's never been a problem. Readings over 3/4 scale bear looking into.

[Quantum-man]

It's the correct place for some gauges. A little high for others. Mine on my Quantum, now sits at between a 1/4 and 1/3. Half way, when up a steep incline if pushed extra hard.

[82vdub]

The gauge will read at different levels depending on the vehicle, the condition of the sensor, gauge cluster, and wiring conditions. In other words, you have to get to know your vehicle. Change the Tstat (even to the same temp), and the gauge may read slightly different.

Climbing hills, I've run ole 82 up almost into the red. Yea, I was sweating that one, but the cooling system is in good shape, and they should be able to take a lot of heat, as long as the coolant is properly being circulated. I want to add a dual gauge setup to monitor coolant temp going to the radiator and from the radiator so I know better when to pull over (still haven't had time). But, running a little higher temp is quite common in these.

As far as the fan is concerned, a diesel at idle doesn't generate that much heat. They can idle for a considerable amount of time before the fan comes on. Just depends on a lot of factors, but the fan must be operational. The old winter Jetta that I retired last year the fan never worked. Didn't care, as long as I was running it in cold temps and if I ever had to stop, I'd watch the gauge. Never had a problem.

[piperpilot26]

good to know its normal!! I'm still fairly new to the whole diesel thing. I learn more and more everyday, especially with the help and support of you guys anyways, I'll keep my eye on the gauge and learn my engine's temp's in different conditions. thanks again guys.


shaun.

[Golf/Jetta]

Very normal for the mk2/mk3 during the hotter months here in Canada.

but once it gets chilly out and I use the heater blower. Doesn't get hot unless I shove it on 2 or 3 (fan speed). Usually 3 even's it out and 4 cools it down below 1/4 (gauge reading) during the winter. -20oC, I Don't even bother turning it past 1. It'll never heat up. Unless I shove a piece of cardboard in front.

[coke]

If you wana be 100% sure, stick a meat thermometer in the coolant expansion tank when its up to temp. My car always read high (between half and the next mark)

Coolant measured 192 degrees. Never bothered me after that. It depends on a lot of factors like the others mentioned. Gauge cluster, wiring, sensor, etc.

[mtran]

Hi
My Coolant measured in expansion tank is 80c 176F,but gauge cluster show 89c 192F give me headache and I take that 80c is important.Orig 79c 175F Tstat.I put manual switch with led for my 2 vent.In summer before hill I ON switch just for piese of mind as I know that will climb,climb more.Best

[82vdub]

In my opinion, the expansion tank coolant temps will nearly always be cooler than coolant circulating to the radiator. The small size of the line leading to the expansion tank is a lot of surface area to the amount of fluid, leading to a higher heat transfer rate, and cooler temps in the tank.

[TylerDurden]

The infra-red thermometer is your friend... you can spot-check the system at numerous points while the engine is running and at full pressure... inlet, outlets, radiator tanks, hoses, heater core...

Also helps to verify degree of air-conditioning chilling.

Temperature range: -27° to 482° F (-33° to 250° C)