Safe Water Temps?

[Chris D]

I just installed an auto meter water temp gauge in my early 99 7.3. and went for a test drive.

the auto meter was reading at 140F at the time the stock gauge reached its normal position (about half way). but the autometer eventually creeped up to about 205 (5th gear at 55MPH) without the stock gauge moving at all from its normal spot. in an attempt to get some airflow i sped up to 75 and the autometer immediatly dropped to 180 degreese, even tho the stock gauge never moved.

1, what is the safe temps for this truck? everyday drive temps and when should i start to worry about it getting too hot?

2, could i have possibly been running this truck at very hot temps this entire time when the gauge reads normal?

[Dietoremain]

Interesting.. wish i knew the answer but im thinking about getting some more gauges myself(water temp, oil temp, etc).

[Reg Bichel]

Originally Posted by Chris D

I just installed an auto meter water temp gauge in my early 99 7.3. and went for a test drive.

the auto meter was reading at 140F at the time the stock gauge reached its normal position (about half way). but the autometer eventually creeped up to about 205 (5th gear at 55MPH) without the stock gauge moving at all from its normal spot. It's an idiot guage and just that. That's why smart fellas put a real guage in to monitor the temps. in an attempt to get some airflow i sped up to 75 and the autometer immediatly dropped to 180 degreese, even tho the stock gauge never moved. Ditto above statement.1, what is the safe temps for this truck? everyday drive temps and when should i start to worry about it getting too hot? 220-240 is not uncommon (depending on ambient temp and workload). Remember that your sender unit is reading the water temp after it has done it's work in removing heat from your block & oil cooler (heat exchange). As this water enters the top of your radiator at this 200+ temp it cools down to 140-160 (about the same temp as your Transmission Fluid Temp if it were a 4R100).2, could i have possibly been running this truck at very hot temps this entire time when the gauge reads normal?

Also remember that even though water boils at 212 Degrees (at sea level) the water in a vehicles system is under pressure and therefore will boil at a much higher temp. As is the opposite in a vaccum. Hence the reason for putting a vaccum pump on a fridge or air con system. Pull a vaccum an any water/moisture (the system killer) in the system boils off at a few degrees and gets sucked out as a vapour.
However I digress, my apologies
I wouldn't suspect that your truck has been running too hot mate. I'm no expert but you sound good to me.


Cheers,
Reg.

[tubular031]

yea what he said... running empty I usually hang around 190 ish. when pulling hard 220+ ish and then the fan comes on and makes the truck moan and groan.

[Chris D]

i found out that the stock thermostat opens at 195 and i drove it to work for a test drive, and sure enough after 205 it opens up and it drops to 180. it then climbs to 205ish and drops again. so im assuming thats when the thermostat opens and closes at a certain temp. im not sure why my stock gauge stays the same but as long as its not overheating i guess im fine. we will see when we hit 105-110 at the beach this summer...