84 ram 250 temperature not building up

[comet240]

hi i just replaced the tstat of the van last night it had one of those safetly tstats that doesnt close, we had it in there cuz it used to over heat and u have to put the heater on high in the summer time to cool it now, i cant get the temperature to build
i replaced the t-stat last night with a regular one and i ran it this morning working out the air bubbles but i must have it all out but i dont get the pressure yet really and the temperature is at 1 notch from the C mark so i wanna know if its an air bubble or if it could be the water pump? but the pump is not leaking and there is no clearance.

any ideas

[alloro]

If it were the pump or an air pocket then you'd be overheating, not running cold. Your problem is with the t-stat. Either it moved when you were bolting it down so that it's off center and coolant is bypassing it, or the t-stat is defective and isn't closed.

[comet240]

oh ok figures ill re look at it tommorow dunno how it could have moved, but if its closed and such what else causes it not to build up temperature or really pressure then cuz i could squeeze the hose but it wasnt tight like u cant squeeze it but there is lots of fluid in it

[alloro]

Originally Posted by comet240

but if its closed and such what else causes it not to build up temperature

A cracked water passage in the intake. The only way the engine doesn't heat up is if coolant is bypassing the t-stat.

By any chance, when you were changing the t-stat did you knock the wire off of the sending unit for the gauge? If you did, the engine could be up to temperature but the gauge just isn't working.

[comet240]

how would a cracked passage get in there? how do i find that? and ill check for wire but right now it warms up to just the first tick mark after C and stays there for when i driving doesnt get any hotter then that but ill check if its off but dunno how if its reading

[comet240]

so wire was still on cuz its like 5 inches away basicly so how do i fix this crack with bardal or something?

[alloro]

I don't think your intake is cracked. You asked what else besides a bad t-stat could cause the engine to not heat up. A cracked intake was the answer to your question, but at the same time, like I just said, I do not think you have a cracked intake.

After say a 10 mile drive:
Does your heater blow hot?
Is the upper radiator hose hot to the touch?

[comet240]

hi to answer ur questions if i drive say 30 min it still stays at the 1 notch mark now if i try to take cap off there is pressure the top heater hose doesnt get tight that u cant squeeze it like my other vehicles i have had in the past. it seems hot and the heater blows hot air that i can tell but then again its only like 14 degrees out

now what i did find is if i drove for a bit like shopping stays at the first notch now i got the the store spend 15 min there or less then i come back i turn key on and the temperature reading goes right to almost H then i start up van and then it slowly goes back down to the first notch once the engine is running its been doing that now so what does that mean

[alloro]

Originally Posted by comet240

it seems hot and the heater blows hot air that i can tell but then again its only like 14 degrees out

temperature reading goes right to almost H then i start up van and then it slowly goes back down to the first notch

I think at this point you need to check the coolant temperature with a separate thermometer. They sell them in the auto parts store for like $5 or so. This could be a simple matter of the gauge not reading right even though the engine is up to full temperature. But personally I still think the coolant is leaking passed the t-stat.

For your second question, since the engine is off when you're in the store the coolant doesn't circulate. Because of that, the coolant that's in the engine continues to absorb the heat from the cylinders. This is why the gauge is up when you first turn the key on. Now once you start it, the coolant starts circulating and the cold coolant from the radiator goes into the engine while the coolant that was in the engine goes into the radiator. This is why the gauge is first elevated, then drops so quickly.

[comet240]

ok ill take it off and re do it again,

i do have a laser thermonitor for doing food and stuff what should the temperature be at and stuff

i just never seen the temperature go sky high before usually sat at the temperature where it last was like on my car

but ill first take off the tstat and then reput it back on

[alloro]

Originally Posted by comet240

i do have a laser thermometer for doing food and stuff what should the temperature be at and stuff

About 180 degrees at the base of the t-stat housing with a fully warmed up engine. Actually a 10 mile drive before checking it would be good, and leave the engine running.

[comet240]

ok i never got to drive it yet but i let it idle for 30 min or so

i retook off the gasket maker i put on and re did it looked fine

so i ran it idling and then laser tempered different locations

at the Tstat - 190ish
at the tstat probe sensor - 170ish
at the top heater hose - 140ish
at the top of rad cap - 160ish
at the top of the rad core - 175ish

does that help at all

[alloro]

Originally Posted by comet240

does that help at all

Yes it does help. All of those reading are reasonable. That means the problem is your dash gauge is acting up or your sending unit for the gauge is no good. Start by replacing the sending unit since that's easier and less expensive.

[comet240]

ok well thats good to know ill try to replace that today if i can get it

priced out the gas tank sending unit from my other posts you reply to
they want 145 bucks and it was hard to find cuz they dont relaly catalogue it anymore just the fuel pump at canadian tire go figure

[alloro]

Originally Posted by comet240

priced out the gas tank sending unit from my other posts you reply to they want 145 bucks and it was hard to find

How about $70...is that better?
http://www.rockauto.com/catalog/x,ca...,parttype,4436

http://www.rockauto.com/catalog/moreinfo.php?pk=872356