80LS1T Posted July 26, 2007 Share Posted July 26, 2007 Well I'm working out a few bugs in my car again before I get it back on the road. One of the those bugs is that my Autometer temp gauge shoots up to 250*F pretty quick. The sending unit is in the drivers side head. Do you guys think this is a good spot for it? I could have sworn that's where it was when I had it running 2 years ago but I know I didn't have any issues with that gauge before? I plan on pulling the t-stat housing tommorow and making sure the block is full of coolant(maybe it's air locked?)(I think Bartman had this issue a while back). I just want to make sure the sending unit is in an OK place before I go screwing around with moving it. Guy Quote Link to comment Share on other sites More sharing options...
deja Posted July 26, 2007 Share Posted July 26, 2007 The sending unit is in the drivers side head. Do you guys think this is a good spot for it? Guy The temp unit on an older SBC is usually in the intake manifold near the thermostat housing, not in the head. Quote Link to comment Share on other sites More sharing options...
m1noel Posted July 26, 2007 Share Posted July 26, 2007 I don't know about the LT1, but on my LS2 the sender is in the drivers side head. Mike Quote Link to comment Share on other sites More sharing options...
deja Posted July 26, 2007 Share Posted July 26, 2007 DOH! Totally missed the LT1 thing. Quote Link to comment Share on other sites More sharing options...
Bartman Posted July 26, 2007 Share Posted July 26, 2007 Well I'm working out a few bugs in my car again before I get it back on the road. One of the those bugs is that my Autometer temp gauge shoots up to 250*F pretty quick. The sending unit is in the drivers side head. Do you guys think this is a good spot for it? I could have sworn that's where it was when I had it running 2 years ago but I know I didn't have any issues with that gauge before? I plan on pulling the t-stat housing tommorow and making sure the block is full of coolant(maybe it's air locked?)(I think Bartman had this issue a while back). I just want to make sure the sending unit is in an OK place before I go screwing around with moving it. Guy I would think you probably do have air locked in your system. The drivers side head is the correct location for the gauge sending unit, but I've read about people using the location that the PCM uses for both the gauge and the PCM. I believe the factory made this modification in later year LT1 engines. Quote Link to comment Share on other sites More sharing options...
80LS1T Posted July 27, 2007 Author Share Posted July 27, 2007 I thought for sure I had an airlock but I pulled the T-stat housing and it was full. I'm going to try bleeding it tommorrow with the front of the car jacked up. If that still doesn't work I'm going to ge a new sending unit for the gauge. I know its not really heating up that much because the car isn't over heating(boiling over) and the PCM is only reading 193-195*F when fully warmed up. I really don't what to mess around with moving the sending unit but I will if I have to! Guy Quote Link to comment Share on other sites More sharing options...
lbhsbZ Posted July 27, 2007 Share Posted July 27, 2007 Moving the sending unit doesn't make the engine run cooler....its kinda like lowering your oil temps by getting rid of the 300° gauge and installing a 250° gauge....all it does is make you feel better. Are you sure that the sending unit is correct for the gauge you are using? Try a cheapo mechanical gauge from auto-zone, they give halfway accurate readings. I haven't had any problems with the autometer temp gauges yet, but their oil pressure gauges suck. I've got 5 of them sitting on a shelf in my garage, obviously disconnected, that still read anywhere from 20-80 psi....the needles stick or something. One of them cost me a motor. I run 2 oil temp gauges and 2 water temp gauges now. Quote Link to comment Share on other sites More sharing options...
80LS1T Posted July 27, 2007 Author Share Posted July 27, 2007 Moving the sending unit doesn't make the engine run cooler....its kinda like lowering your oil temps by getting rid of the 300° gauge and installing a 250° gauge....all it does is make you feel better. Yes I realize this but I am wondering if the header is giving off excess heat and causing a false reading? Guy Quote Link to comment Share on other sites More sharing options...
lbhsbZ Posted July 27, 2007 Share Posted July 27, 2007 Nope, doubt it. I just finished an install in a camaro, with the temp sensor in the head (mechanical) an it reads like it should. If the gauge reads 250, it means 250....something is wrong. Quote Link to comment Share on other sites More sharing options...
Bartman Posted July 27, 2007 Share Posted July 27, 2007 Guy, do you have the bleed screws on your coolant system? In order to get all the air pockets out, you generally need to bleed the system. If you're shooting up to 250 relatively quickly that's generally a sign that there's air in the system. It happened to me when I upgraded the top end of my engine, and once I got all the air out it went back to normal range. edit: http://shbox.com/1/4th_gen_tech2.html#radflush Quote Link to comment Share on other sites More sharing options...
piston Posted July 27, 2007 Share Posted July 27, 2007 on the camaro, the temp is on the driver side and the caprices had them on the passenger side... Quote Link to comment Share on other sites More sharing options...
80LS1T Posted July 28, 2007 Author Share Posted July 28, 2007 Yeah I still have the bleeder screw in the t-stat housing. I am trying to bleed it right now. It sure does seem like there's air in the system, I just need to get it all out! Quote Link to comment Share on other sites More sharing options...
pparaska Posted July 28, 2007 Share Posted July 28, 2007 You'll have a lot more issues with the sender getting uncovered (being dry, in an air pocket) and giving false readings if it's in the intake manifold. Due to this, I paid Canfield and extra $25 for them to do the CNC programming to put temp sensor holes in my heads. With these cars the radiator opening is generally not the highest point in the system and requires you to do what Glenn McCoy told me is common for the old Fiats: Jack the front of the car up until the radiator opening is the highest point in the system. Start the car and get it warmed up. Rev to about 2000 rpm to clear the air out of the system and keep adding water. Don't some cars come with an air-break type bleeder that is in the thermostat housing or something that constantly bleeds out the air? Anyone know of such a part? Quote Link to comment Share on other sites More sharing options...
Danno74Z Posted July 28, 2007 Share Posted July 28, 2007 On the LT1 engine there is no coolant running in the intake manifold. There is a steam pipe that connects the left head to the right head on the backside of the engine. From this picture you can see the bleeder screws. Danno74Z Quote Link to comment Share on other sites More sharing options...
80LS1T Posted July 28, 2007 Author Share Posted July 28, 2007 I have that steam pipe connected to my lower radiator hose. I don't have a bleeder in it though. I am beginning to think it's not an airlock and just a bad sensor. I am going to try again to bleed it this afternoon after I get off work, we'll see I guess. The sending unit for the gauge is only $14.00 from jegs(just sucks I have to wait 3-4 days to get it!). Guy Quote Link to comment Share on other sites More sharing options...
80LS1T Posted July 28, 2007 Author Share Posted July 28, 2007 Well I'm pretty sure its not an airlock and that it's not really getting up to 250*F. Datamaster says its at 209*F at its hottest point. Another thing I noticed today was that the guage went up slower that it was before, so maybe there was an airlock before causing it to shoot up really fast? I ordered the sending unit today so I should get it by Tuesday. I throw that in and see what happens. Its running pretty good otherwise! Got some tuning to do though! Guy Quote Link to comment Share on other sites More sharing options...
Bartman Posted July 29, 2007 Share Posted July 29, 2007 Well I'm pretty sure its not an airlock and that it's not really getting up to 250*F. Datamaster says its at 209*F at its hottest point. ... This is a good indication that you do have an air pocket. The air pocket would likely be in the head allowing the gauge to indicate high temperature while the PCM detects the actual water temperature from the water pump. I think as you get more and more of the air out, the gauge is going to shoot up slower until you eventually get it all. It's difficult with only one bleeder screw. Do you have the heater hooked up? You should have that on if you do as that will have air in it as well. I think your gauge sending unit is fine, but we'll see. Quote Link to comment Share on other sites More sharing options...
80LS1T Posted July 29, 2007 Author Share Posted July 29, 2007 You know Bart I completely forgot to turn the heater on. I probably should do that. Oh and after the car sitting for the last 4 hours the temp gauge still read 170ish! I really doubt it's that hot in the head after 4 hours. LOL I really want to drive it further(just taken it around the block so far) but I would like a temp gauge that works properly! Guy Quote Link to comment Share on other sites More sharing options...
heavy85 Posted July 29, 2007 Share Posted July 29, 2007 To check if there is air around the sender have your backed the sender out and listened for air coming out or is it all water? Cameron Quote Link to comment Share on other sites More sharing options...
80LS1T Posted August 2, 2007 Author Share Posted August 2, 2007 Well after atleast a dozen heat up to cool down cylces it still didn't chagnge anything. So I ordered the temp sensor from Jegs on Saturday. It was my 8 year anniversery with my woman yesterday so I obviously couldn't put that sensor in yesterday after work. So tongiht I put the new sensor in and I am happy to say that was the problem. My guage now reads 200-210 after being warmed up and stays in that range while driving! Hope that helps someone! Action video's soon to follow! Guy Quote Link to comment Share on other sites More sharing options...
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