Truck blows cold when I stop

[02exploderx]

Hey guys ran into a problem and need some help diagnosing it. Last year same thing happened but it went away and forgot about it. This year it has come back and its a really cold winter. It blows hot as long as you are driving as soon as you stop at the light it blows cold. But if I pull up to the light and keep the rpms up then it will still blow hot. So I am stumped as to what it may be, local parts place said to start with the thermostat but I thought it might have been something different? Any ideas would be greatly appreciated!!!! thanks!

 

[BigRondo]

How is your coolant level? Thermostat? Might be a vacuum issue.

I will check my shop manuals and will gather some good info and send it to you.

You are 4th in line so please be patient.

Please keep us posted as feedback helps others reading this post looking for a fix to the same or similar issue!

 

[BigRondo]

I assume that since you have a limited, that you have DATC. Can you please verify?

Thanks.

 

[corkey]

i say coolant level is down,,

 

[02exploderx]

yes

I have the 4.0 liter V6 and yes its datc. coolant level seems to be correct. It doesn't leak any antifreeze that I know of I have seen a few drops here and there in the driveway but it could be my olds alero doing that. but I will check on the coolant and verify levels.

 

[trucku]

Low vacum on valve that allows coolant to flow into heating core. At idle you don't have enough vacuum to keep it open.

Just a guess!
Good Luck

 

[02exploderx]

j

How would I find this vacuum leak at the valve? Sounds like a simple fix if it is in fact something like that! Thermostat seems fine when I slow down it doesn't dip down in temp. or anything like that.

 

[BigRondo]

I am putting together the troubleshooting steps for you. Please be patient. I should be able to work on it when I get home tonight.

 

[02exploderx]

fix

So I added about a gallon and a half of coolant to the truck today and it heats like a dream where would I have lost so much coolant?? I have never seen anything on my garage floor and it runs like a champ decent gas mileage and doesn't smoke or anything like that? Any ideas??

 

[trucku]

So I added about a gallon and a half of coolant to the truck today and it heats like a dream where would I have lost so much coolant?? I have never seen anything on my garage floor and it runs like a champ decent gas mileage and doesn't smoke or anything like that? Any ideas??

Do you ever smell a sweet smell? If you have a bad resevoir cap, not holding pressure, your coolant will escape that way. Does the top hose get firm when the truck it completely warmed up?


Good Luck!

 

[02exploderx]

cap

I do remember smelling something the other day when I had the truck running for a couple minutes and I took the cap off to put the gallon and a half in I smelled something kinda sweet when I opened the hood up. So maybe replace that res cap and I checked the hose and thats super tight on there.