heating question.

[Wayne P.]

Here are the temperature readings . with rf gun
Findings
upper rad hose 174 183
Lower rad hose 168 174
Gauge 230 240

Interesting only boiled in overflow tank when engine turned off.
Might require new sender unit in intake ?
Thanks for any help
327 365 cam solid lifter

[William S.]

Re: heating question.

Wayne,

Two years ago I had the same experience with "overheating", unfortunately I did not have a I.R. device. Mine was a sending unit in the manifold. By the way I replaced every thing else before finding the cause.

Bill

[Jack H.]

Re: heating question.

Here are the temperature readings . with rf gun
Findings
upper rad hose 174 183
Lower rad hose 168 174
Gauge 230 240

Interesting only boiled in overflow tank when engine turned off.
Might require new sender unit in intake ?

OK, you've done the hard part (verified engine coolant temp isn't what's being reported on the cockpit gauge). Now, you have to separate whether the fault lies with the temp gauge or the sender...

Verify the gauge by disconnecting the temp sender wire and connecting it to ground via a fixed resistor. Note, engine ought to be warmed up, idling, with alternator clamping the battery to aproximately 14 VDC...

If the gauge is in cal and properly grounded in the instrument cluster you ought to see:

100F = 350 Ohms
210F = 75 Ohms
250F = 50 Ohms

If you don't, it's the temp gauge calibration and/or installation (grounding). If you do, time to go source a better temp sender...

[Wayne P.]

Re: heating question.

Thanks will test tomorrow. I am a novice. Do I attach the wire from the heat guage to one side of my ohm meter ( Red )and then ground the black to intake or sending unit.? thanks

[Wayne W.]

Re: heating question.

My opinion from experience, rubber hoses dont relate well with an IR gun. Best to take the readings on the actual metal radiator outlet and on the thermostat housing etc. I dont get accurate readings on hoses. If it is boiling anywhere, it is hoter than those readings, more like 212+.

[Wayne P.]

Re: heating question.

Wayne I will try a aftermarket thermometer and attach it rad outlet and housing. thanks for input.

[Timothy B.]

Re: heating question.

Wayne, Is that radiator cap holding pressure?

[Wayne P.]

Re: heating question.

Timothy good question. Not sure. I guess any automotive shop would be able to test it. I think it is 15 LBS> Thanks

[Jack H.]

Re: heating question.

Thanks will test tomorrow. I am a novice. Do I attach the wire from the heat guage to one side of my ohm meter ( Red )and then ground the black to intake or sending unit.?

Dah??? If you do that you'll be measuring the effective resistance of the temp sender lead wire back through the temp gauge to ground. Is there some reason why you want to ohm-out the temp gauge's inductive windings?

What I said was to splice fixed resistors between the temp sender wire and ground (in other words substitute these resistors for the temp sender itself) to verify the calibration accuracy and installation integrity of the gauge as its installed in the instrument cluster...

[Wayne P.]

Re: heating question.

Jack told you I know very little about electrical wireing . Will give info to a
expert. Beyond my skills. Thanks

[Wayne P.]

Re: heating question.

One other question came up should I be running a 50/50 glycol mix
or adjust the level of water to glycal to lower temp . I will check cap 15 LBS might have to increase to 17 LBS thanks

[Dick W.]

Re: heating question.

One other question came up should I be running a 50/50 glycol mix
or adjust the level of water to glycal to lower temp . I will check cap 15 LBS might have to increase to 17 LBS thanks

50/50 mix will give you the maximum protection, both for corrosion and freezing. I would drain the system and refill with a mix of Zerex G-05 and distilled water.

[Wayne P.]

Re: heating question.

Dick is prestone different than Zerex ? New antifreeze put in . thanks