cooling problems

[84 400]

I tried the search function first but have come up empty..

Anyways here is the issue.
Just did a water pump, 180 T stat, new coolant temp sensor. I must be missing something here because it keeps over heating.

If I start it with the cap on it heats up and will go over. I then remove the cap and let it run and the temp drops down. While running if I recap it will not over heat. But next time I start it with the cap on... Bam over heat.
First fire up with cap left on and it runs good. but the heat starts rising. Remove the cap and the temp drops to normal opeating temp. then put cap back on and it is running fine. won't go over and rins fine. turn it off and refire and it rises over again remove cap and it drops...........
I am guessing this is air in the system???? IS this an air pocket issue? The T stat cover has a bung in it does this need to be removed or is that just for an accessory?

I tried squeezing the top hose with the cap off and it running to work out a potential air pocket and the level dropped but then today when I fried it up it got hot again..... removed cap with it running temp went down ect.......

Please feel free to re educate me on what I am doing wrong. I have been wrenching on it hard for the last week trying to get it inspected tomorrow and need to get this figured out.

Thanks

[CoggedBelt75]

Responded in the engine section so will do the same here....If the over heating wasn't an issue before the changes you made, I would test the thermostat. Learned this first hand...ordered a high flow t-stat from Summit, installed it, drove it around a bit and it kept puking out water. I also thought about an air pocket since this didn't happen before I changed this. But for grins and giggles, I pulled it back out, grabbed a thermometer, threw the stat in a pan of water and heated it up. Got to a rolling boil and it never did open up!!! The brand new t-stat was defective!!! Replaced with another from local speed shop and runs 180*-195* even on the hottest day. Just something to think about. Hopefully, it's something as simple as this. Just because it is new doesn't mean it is right.

Joe

[asphaltburner]

Yo!
Wierd!
I'd have to agree with CoggedBelt75.
And while you have the Tstat pulled, test it in a pan of water,...you'll see it open if it's good. Then fill the block with any coolant necessary. That will for sure remove any air pockets. Replace a working Tstat in the proper orientation in the housing, close the system, and fill with coolant to the proper level.
Cap off drops the pressure in the system and actually reduces it's heat carrying capacity, so it's probably due to something else.
All else sounds proper from your description. Tstat is the most suspicious,...perhaps in addition to an air pocket.
Wierd,...wish I could give you a for sure, 84 400. Good luck. Post with results, please.
Todd.

[blaserman]

If you think you have air in the system put the truck front on a set of ramps that will force the air to go towards the rad. I have always done that when I flush the system and you would be surprised on the amount of air that comes out. But like everyone else I also think it is the stat.

Art

[dammitmitchell]

agreed t stat..

[James McClure]

400. I agree with the other folks. Put your stat in a pan of water and boil it and see what happens. If it opens, OK. Next step. With the eng COLD look at the rad hoses, especially the lower. Is it collapsed? If it is you need to put the "spring" in it. Next, is the recovery system working correctly? It won't if the lower hose is collapsed. Next, put your cooling system pressure guage on and have someone start the eng. If the pressure comes up right away you have a combustion leak into the water jacket someplace. Just in case, the spring side of the thermo faces the intake manifold not the radiator. Good luck, jim

[84 400]

threw in a new stat... No luck. Does the same old Sh*t....

Tested both in a pan of boiling water and both function as they should
'

Should I see flow in the rad? the water does not seem to be moving very much at all..

It already has the spring in the bottom

[dammitmitchell]

hey umm.. i did this once.. not saying you did.. but pull your hozes and make sure that there isnt any shipping container stuff or a rag in teh radiator inlets/outlets..
jsut an idea =-)

[James McClure]

84, is there an outside chance they gave you the wrong waterpump for your truck? Mabey they gave you a pump for serp belt setups, just a thought. If you did all the tests and eliminated head gaskets, failed stat ect, whats left? Is rad ok? If you have A/C, look at the front of the rad and see if it's covered with leaf debris ect. Otherwise I'm stumped. Let us know what fixes it. jim

[Lakewood90712]

Head gasket leak or small crack in the head. I had one with a bad head gasket , only did it in cool weather after a cold startup. Someone makes a test kit , samples the coolant for tiny traces of combustion gas.

[84 400]

Tried elevating the front end and no luck.

There is no flow in the rad at all with out the cap on and the lower hose does not seem to have any suction I have a spare pump and am going to give that a try..

[dammitmitchell]

have you tried an actual radiator flush??? it does wonders...
maby your radiator is screwed.. might must wanna super clean that bad boy

[asphaltburner]

Yo! 84 400!
Prior to your work everything worked, correct? Ya just needed to replace the waterpump. So there's your "baseline". The new parts, or processes to install them, are the failure.
New temp sensor? Is the engine truly overheating, or could the sensor be defective? Or incorrect application?
Did you fill the block while the tstat was out?
Proper application waterpump? And (not that I can imagine how it would be possible!) but is it functioning properly,...belt turning the pulley? Do the radiator hoses get hot?
Geeze this is weird,...but you've got the baseline of everything working prior to the work that was done.
Go from there and don't let a molehill become a mountain by questioning things that weren't defective prior the the new parts.
I SURE want to know the answer to THIS one!!
Best of luck, Todd.

[lolife99]

James McClure had my idea. Maybe you got a reverse rotation water pump for the serpentine style engines. That means it would be running backwards on a standard v-belt set up.
Years ago,... I had a water pump problem that I couldn't figure out. Part of the problem was my brand new rebuilt "Parts House" water pump. So I try to buy new, not rebuilt .
I really like Edelbrocks aluminum water pumps.

[84 400]

Thanks for all the replies. I went out and got a diffent pump. The collent level did not go down untill I put the cap on then it dropped?

Should I be seeing some flow in the system? On my black truch it looks like a waterfall the water is flowing threw so fast. This one it looks calm and flat. Going to get some more coolent now and see what it does.

[84 400]

First off thanks to all the members of this board who offer ideas and helped with this problem.

I swear this truck was out to get me on this cooling system issue. I took off the napa pump yesterday and it was 5 degrees out. To complicate things our under ground power had a fault so we had no power all day. I don't have a heated area to work on it anyways and this last week has been pretty cold. So anyways I got the napa pump off yesterday afternoon and once it got dark I called it quits and cleaned up a spare used water pump I had sitting in the basement. Today I found out it was different so I sucked it up and bought a another new pump. Put it on and it has not over heated since.

So I guess the napa pump must have been defective. It was a remain pump.


Thanks again

[asphaltburner]

Yo! YEA!!!
Sorry about what you had to go through to "get 'er done", but I'm quite relieved that your truck is functioning properly!!
I heard your weather has been hell!! Nearly embarassed to say ours' was beautiful today for a change,...so I was able to accomplish quite a bit (comfortably!)!
I've not run across a bad waterpump, but with todays' quality, it doesn't suprise me too much!!
Todd.

[CoggedBelt75]

Glad to hear your problem is solved!!!

[84 400]

thanks todd and coggedbelt75

[dammitmitchell]

sweet guess im the only on to ever leave a rag stuffed into an inlet.. dang..

[James McClure]

Hay Todd, stick your pleasant weather and take some of ours!!! LOL. Been snowing 24 hours now and we have gotten 12 to 14" on top of the 2 feet we already had!! Did I mention, I HATE WINTER!!! Glad 84 got his mess fixed. I've seen bad NAPA waterpumps in the past, but generally thier stuff is pretty good, IF you buy the higher priced option, but even at that they are better than Auto Blown or Parts Afganistan. You all know who I mean. At least the guys at NAPA know "rear" is in the back and front as the end with headlights. LOLL, jim

[84 400]

Yeah jim I hear you on the Weather. We got that bitter cold ice and has been snowing now for about 24hr.

I am a NAPA fan. The guys there often know what they are talking about and sometimes offer some good tips. I wonder if they are required to know more to work there?? I also Like some of the local small chain stores because they offer better hours then NAPA and are local.



I kinda wish we had an o'reilies and or checker around here because I have never tried them.

[James McClure]

84 we aren't all that far appart. I live near Albany where are you at? Takes me about 5 hours to get to Hampton beach from here running 7 thru the mountains. Glad they got this end of 7 finished. jim