temp sending unit question????

[kxnomore]

Can installing a new temp sending unit change the location of the needle on the temp guage? I changed out my cylinder heads this weekend after I had some bad valve issues, and the shop lost my sending unit. I picked up a new one from Kragen, and now the guage is reading in the middle of the guage, not down on the lower range line like before. It may be psychological, but seeing the guage up there freaks me out.

One note is I switched to larger chamber heads which were supposed to help with a bad pinging problem, and it might be possible that the new heads would make the motor run hotter?

Anyone had this happen before?

[sneakysnake]

If the ohms readings are the same on both sending units(meaning didn't get the wrong sender) then its possible the old one may have been reading wrong or the new heads or timing may be effecting the temp.

[basketcase]

Also keep in mind that the sender grounds through it's threads to the head. Thread sealer will often insulate the sender and cause false or even no reading. They are brass for a reason. They will tighten leak free with clean bare threads.

tom

[kxnomore]

Thanks for the replies. I don't have the first sending unit to check the ohms. But I did install it with no sealant or teflon tapes. Just the fitting into a brand new clean head. I am hoping it's just due to the sending unit itself. I don't know of anything else that would cause it to run hotter? I used the same thermostat, timing gun, everything. Even going downhill and just cruising the guage reads straight up.

Unless someone thinks it's worth trying a different sending unit, I may just learn to live with it...

[Longhorn Man]

your new heads should make it run cooler, not hotter. (open chaimber, lower compression) but it would be marginal at best in the coolant temp.
Your old sending unit was probably covered in desposits and slime and crap, which acted as a thermal barrier, so it was giving a false reading of a too low temp.