wro87

My buddy has a 85' the temp gauge reads high while going down the road over 240deg. have taken the sender out of the head on the drivers side and put in an analog gauge and hooked up a snap on scanner to the ecm. When out on the road they both say about 180deg but the lcd one says 240plus, hell it will get up to 300 and the red warning light comes on but the scanner and the analog gauge still both say 180. Could it be the sender on the block but then why does the scanner say the same as the analog gauge? or could it be the lcd unit everything else on the lcd screen seems to be working fine it seems to be just the water temp side. Any ideals gang?
thanks wro87

K87ZZ4

I'm trying to remember, for sure, how many coolant sensors there are on the 85--2 or 3, I think, depending on the year. I'm sure someone who knows the 85, for sure, will chime in.

Have you burped the system to make sure there's no air trapped?

I doubt it's the display if the numbers are changing and the warning light is coming on.

wro87

Thanks for the reply zz4! Well we seem to have the one by the water pump and the other on the dr.head. We do have the FSM and looking for more information. The thing that really bother us is the scanner showing only 180 reading it oof the link and we would think that the dash readout would be saying the same thing. Well we will keep looking! He does have in the works to repalce the waterpump with the Elderbock unit and the sending unit on the front and drivers head.
Thanks wro87

HlhnEast

My '85 runs at about 185* at normal driving, occaisonal fan action at lights. Definately sounds like a false reading. If it aint puking water, dont worry about it. You can replace the sender, the guage, the wire all of it, to get it right but it will only satisfy you, the engine is fine if no water is coming out. JMHO.

AGENT 86

Scanner is reading coolant temp from sensor in intake.
LCD is reading coolant temp from sensor in head.
Sounds like a bad sensor in your head. , or short in wiring.
http://members.shaw.ca/dankai/Fuel,C...%20Display.gif

wro87

Thanks Agent86.
We were leaning that way as to bad sensor or wire have found a couple of bad wires from PO (it appears he could take stuff apart but could not get it to go back together). So now the hunt is on.
wro87

Demonic85

'85s have 3 coolant sensors. Driver side head goes to the LCD, passenger side head is for the fans, and the one in the front of the intake is for the ECM reading. So I agree with Agent the LCD sensor/wiring is messed up.

gerardvg

Hi i have an 85 and the drivers side sensor will get screwed if the engine got hot .. i have replaced my cars temp sensor twice and yes it will show very high temp when the engine is at normal temp .. did mine when the radiator hose failed. also if you are not sure the oil temp can be viewed it will be close to the water temp .. good luck !

wro87

Thanks for that info but it is still reading HIGH with all the the damn wires disconnected. Going down the road it reads 150deg but as soon as you smash the peddle it jumps up to 300deg and as soon as you let off the temp drops ,Remeber the senders are disconnected. Any ideals GANG?

Thanks wro87

AGENT 86

Sounds like a short in the wiring from sender to LCD. The massive torque of the L98, may be pinching the wire somewhere.

wro87

Thanks 86' that is what we are leaning toward we had found where the PO had messed with some of the wiring and going in that direction. Still replacing the waterpump and will put a new sender in the dr. side head.

thanks gang wro87