Need Insight : Forward oil coler lines don't ever get hot...

pkfrdh · pkfrdh's Garage

My forward oil lines to my forward auxilliary cooler don't get hot even when my temp guage reads 210 to 220 degrees. It is as if the thermostat is not letting oil go forward at that temp. The car has a 1977 temp. guage and a 1978 motor's temp. sending unit. Is there a non-compatibility problem with the early temp. guage and the later sending unit? Does the 1978 cars take the same sending unit as the 1977 cars? Is it possible my sending unit is reading hotter than the oil is actually getting and my oil temp. is always under the temp. the aux. thermostat opens up at?

The lines are hot to the auxilliary thermostat...I just can't seem to get the motor oil hot enough to open up the thermostat to send oil forward. The temp. never goes above 210 to 220 on the gauge. The thermostat was flushed clean and tested to open up and allow air to pass through it when the thermostat body was heated in boiling water (no water was allowed inside the thermostat)...a test my mechanic devised after breaking his tool trying to open up the two screw caps ...and never getting it open. He was going to measure the internal springs to see if they were still in spec. We had to flush it clean by shaking it for hours w/ successive ATF applications until it stopped producing black sediment. The fact that it opened up and allowed air to pass through indicates it still functions at temp.s close to or at boiling water at sea level.

Thanks for any input on the compatibility of the sending unit and gauge.

JGL

makaio · 11-23-2002, 04:10 AM

It sounds like your t-stat is not operating.

Have you checked the oil lines going to the t-stat with an IR temp gun?

pkfrdh · pkfrdh's Garage

I had my aux. thermostat taken off and cleaned and tested and the valves opened up when the housing was immersed in boiling water (no water got inside housing) and compressed air was able to pass through the thermostat indicating it opened up at 210 degrees. It was cleaned out and alot of black deposits came out after it was tested. Clean as a whistle now.

Do most shops have the IR guns to check temp?

JGL

john70t · 11-23-2002, 09:39 AM

They are about $100, and work well for checking if the cat is working and exhaust temps as well

47silver · 47silver's Garage

i posted on another thread, but i think that your thermostat may open at 220 i think you can get new inserts that open at 180 or so. check out the other threads on oil thermstats.

dean · 11-23-2002, 12:49 PM

It sure sounds like your thermo is stuck shut or the lines are crimped. My thermo opens when my gauge reads 8:00. I don't know what temp that is. If I am just tooling around and it is 70 degs out my lines are hot.

marcesq · marcesq's Garage

The '77 guage that has numbers (80, 170, etc) is not compatable with the sender the was used for the SC guage that has color coding.

The proper sender for the numerical guage is available from our host.

This can be verified by the wrench who probably has some kind of a oil temp meter that can be inserted in the oil tank.

Good luck.

dickster · 11-23-2002, 11:23 PM

i have this on my '86 (uk climate). i don't know how similar the systems are but heres my story.

the only method i have for getting the oil hot enough to flow up front so i can check the level is to let the car idle for 20-30mins. the gauge then goes up to just over the second white bar (about 8 o'clock?). then it opens.

the thermostats rarely fail.

the lines in front of the stat before it opens are too hot to touch on mine.