Ok this has me a little befuddled, Without warning a couple weeks ago the water pump (327) on my sedan went south. Thinking it might help I replaced it with a high flow one I picked up here locally. Now since this has been done my temp gauge has become fairly erratic rising from 170/80 upwards to 230/40 and back down again. At first I thought it was a bad thermostat so I replaced it and also drilled a 3/32 hole in it to help purge the air out. Well last night we went for a cruise and it started again, BTW It really doesn't matter if I'm sitting still or at speed when it decides to rise it will. On a side note while I was at it I also replaced the intake(air gap) And other than having to move the heater hose off the intake to the top of the water pump everything is good(ie timing,eTc). Could having both heater hoses on the water pump cause this or am I missing something else?
Did you put the sender back in exactly the same spot on the intake? I guess from your post that you never had this issue before the pump going out. What temp did it always run at before? Don
If you don't flow water past the thermostat, it won't heat up and open properly. If you had a heater hose on the intake and one on the pump you basically had a way for the water to circulate under the thermostat and make it open. Now, the water doesn't circulate under the stat and gets trapped in the heads heating it up. The little hole in the stat probably helps but not enough. Plumb some sort of byp*** from the water pump to the intake near the stat and you will probably fix it. You don't happen to be running Vortec heads are you?
I'd get an infrared temp gun to verify that the engine temp is actually fluctuating and not just false readings on your gauge.
Yes. Before it would run about 190 and never move. No vortec heads. The problem is where the heater hose went in the old intake I had room for it but with the new it's blocked by the AC(I know) compressor so I had to move it to the pump.
yep...loop the heater hose if at all possible? You could try removing the stat all together as an experiment It really sounds like an air bubble to me? Also using an infrared heat gun would be a good idea because I had a seNding unit on my Autometer gage **** out on me once!
sounds like the pump is just recycling the water . not allowing a steady flow to the radiator . can you put a different fitting in the manifold ? as a 90* or 45* to get past the a/c ? .................. steve
Clamp off the hose and see if it stops,if so rerout back to old spot somehow or fine a way near back of heads
my 2 cents,take the heater out of the equation just plug the water pump connection for the heater and see of your temps still jump around.
A clogged radiator could cause funny things as well if its slowing down the water flow. Sound like you got everything else pretty much covered. Or run it without the thermostat to see what happens, a new defective part is not unheard of. Cesar
No there's less than 1/2 an inch between the ac comp and the fitting hole. Thats what I'm going to try.
I went and tried that and there wasn't any difference Radiator isn't that old and the thermostat I replaced thinking that was the issue. I'm starting to lean towards the sending unit but I never had any problem before this although I know it could happen anytime I guess. I also thought about using one of those caps with the temp gauge in it but have been told they are worthless.
The solution to your problem is a simple one. Get rid of the hi-flow water pump. I had the exact same thing happen and tried everything (and I mean everything!) Finally my wife suggested that I go back to an OEM water pump. Aw, what does she know, right? Well I took her advice...............and problem solved. She'd recognized that I didn't have any problem until I put on the hi-flow pump. The hi-flows work for some people I guess, but not me. I had a post about it that I can no longer find, but a HAMBER in Georgia PM'd me months later to say thanks. He'd taken my advice on his BB Chevy truck and finally was able to drive it to a show. Have a great Labor Day weekend!
Funny you mention that. I didn't think much of it but a friend at the cruise in we were at last night said the same thing something about the water flowing to fast causing the thermostat to partially close which in turn causes the spike.
" I also thought about using one of those caps with the temp gauge in it but have been told they are worthless. " I had the same doubts about them, but they do work and come in handy when working on a running engine. Very close to my dash readings. If you should buy one, Ebay has them at about half price of Summit. Remember the old cars had them back in the 1920s' , I always thought that was a pretty good idea. Traditional even, maybe?<!-- / message --><!-- sig -->
I think all the air is out. I was adding to the recovery tank because it was going down quite a bit but now it's leveled off. Yep they're all good. Will do. The local advance here carries them and I might still get one and go for a drive and try it out this evening.
No, those Mr Gasket caps with the thermometer in them are actually very good and accurate. I have one on my 27 as a verifier and it reads exactly what my infared gun does. Don
Well I figured I'll try it I went to our local advance and picked up one. I just have to wait for it to cool a bit before I can put it on.
Here is something else you may look in to.we were fighting a heating problem on our circle track car earlier this year and put a high ouput pump on.it didnt help and maybe made problem worse. Called the speedshop about the problem.they said that the new pump required a high performance thermostat as well. You dont get enoughflow through a stock part. Just a thought
Ok I put the thermocap on and started it back up, Once it got to operating temp both gauges read about the same although when it spiked a bit the radiator gauge barely moved. Funny thing is when I shut it off it puked a bit out of the recovery tank which it hasn't done before (maybe the old cap was going bad?). Lexington that was brought up last night also when we were talking about the high flow pump causing problems.
Problem started with the high flow pump. Does anything more need to be said? To try the thermostat theory, take your old stat and cut the guts out so you only have a restrictor plate.
X2 Friend Had a camero once we did tge hi flow pump no sat and it still ran hot - bought a three different size restrictor set used the mid size -mr gasket i think- and it slowed the coolant long enough in the heat exchange (radiator) to allow the fluid to dissipate the heat. Crushed hot august nights in 99 with that set up and worked well there after
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