I finally got her running, just need to work out a few bugs.

I'm very excited to say that I got my 89 k1500/LQ4 running this morning. It runs better without a MAF, and O2 sensors than my TBI 350 did on its best day LOL.

Anyways, I have just a few issues I need some help with. They are both cooling related.

I don't know whats going on with my cooling system. Both heater hoses get really hot but the upper and lower rad hoses aren't. It has a brand new thermostat (187 degree) and there aren't any leaks in the system. I thought there might be an air pocket in the system (which there still might be), but when I was filling the system, I filled it from the upper rad hose first with the throttle body line disconnected to fill up the block. Once I got a steady stream of coolant from the throttle body line I hooked it back up and filled the rad. I even jacked the front up and ran it for a little while with the cap off. Like I said the heater hoses got REALLY hot and there was some steam coming out of the rad. This leads to my next problem...

I couldn't tell how hot the system was because the temp gauge was only showing 150 degrees. I'm using a 3 wire coolant temp sensor from an F-body. I heard that the F-body CTS can give inaccurate readings (10 to 15 degrees off), but this just seems WAY off. I don't think the rad would be emitting steam if it was only 150 to 160 degrees. Maybe the earlier obs trucks (88-89) with moonie gauges just aren't compatible at all with the 3 wire CTS?

Any insight would be immensely helpful. Thanks!

that temp seems a bit low especially since you have the 190* tstat. i was having trouble with mine at first but it was overheating. so i was driving without a tstat for a while which let it basically run around 120* came to find my problem was that i only was filling the rad and not the block (like you mentioned you already did) so thats not your problem. once i filled the block, it does not go past 190-195 which is where you should be too.

what are you getting your readings from? your old 89 gauge? if so why arent you using the stock SENDER for that gauge from the old motor? then you know it will be accurate. if you have a decent scanner, you can also get the readings from the computer which uses the LS temp SENSOR. i compared my scanner to the cluster gauge and it was almost spot on.

i know im not being too much help, im just giving you some food for thought. but if i was you, i would just use the stock sender and be done with it. you know it will show the accurate reading on your cluster. but this should def be sorted out soon cuz obviously getting too hot could kill your new motor. but im glad to hear you got her running! and i agree, the LS on its worst day is better than a tbi on its best. ha!

Thanks, kewljay. I am getting my reading via the 89 gauge. I had intentions of running my original sender until I read that the 3 wire F-body sensor/sender would work. I wanted to keep it as clean as possible, and I heard that using the passenger side head for the 89 temp sender would create clearance problems with the rearmost spark plug wire. If it's readings are extremely inaccurate, I will just add the old sender.

I haven't wired up the obd2 plug or the check engine light yet. When I do I'm sure I'll get a good reading through a scan tool. Until then perhaps I'll try an infrared temp gun to give me an idea if it's actually getting as hot as I think it is.

infrared gun is a great idea. that would work for sure.

as for the old sender being a tight fit, your right, i got the adapter and it was a pain in the ass. there is a link or thread on here somewhere that says to just grind down the old sender and tap it with the new metric threads so it jsut screws in. after having problems with the adapter i said screw it and went for it. worked out like a charm. since your old one isnt being used anyway, might as well give that a shot.

I got mine running today finally too. I have the link right here http://www.impalassforum.com/vBullet....php?p=2667060 I did this myself and worked great reads accurate and doesn t leak

thank for posting the link. i was gonna try and find it tonight after i got done working on my truck. its really not that hard. takes mybe 30 min if you have a bench grinder and the tap on hand.

I have the 3 wire sender like you in my 1992 pickup and it works perfect. I would say you have anair pocket somewhere. Where did you run the steam vent hose to? I tapped my water pump for mine. Run the truck with the cap off once the thermostat opens so you get all the air out and rev it a little (2000rpms)while cap is off . That always works for me. I had the original temp sensor in the passenger side head and it was a real pain to get to #8 sparkplug that way with headers. That is why I switched to the 3 wire.

Thanks for the pointers, everyone.

I'm running my obs radiator, so I ran the unused heater hose input on the radiator to the steam hose via a 5/8" to 1/4" adapter.

Gagliano, does your truck have the moonie gauges also? I wonder if the resistance is different? Maybe there is some kind of resistor I could wire inline with the gauge wire?

do What gagliano7 said and after bout 30 MIN filling and reving the engine let it set at idle for another 30 mins, at idle is where a car get it hottest point!