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1994 Deville
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Discussion Starter #1
would a clogged heater core make a engine overheat? we seem to be overheating or running hot. trying to narrow this down.
1994 concours N*
 

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99 Seville STS, 08 STS4 N* 1SG F55
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Re: would a clogged heater core make a engine overheat

Nearly impossible that the heater core is causing overheating. Other posibilities:

Stuck thermostat
Plugged/clogged radiator
Failing water pump/slipping water pump belt/failing tensioner
Headgaskets going or getting ready to go

Is it using/losing coolant?
 

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1994 Deville
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Discussion Starter #3
Re: would a clogged heater core make a engine overheat

we replaced the radiator a short time ago as well as the termastat and rad. cap. its hard to get all the air out of the system. i turned on the heater and cold air came out?
 

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1994 Deville
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Discussion Starter #4
Re: would a clogged heater core make a engine overheat

my son drives it and tells me the coolant hot comes on or coolant low we don't see any on the ground put we can add some???
 

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1996 Deville (sold), 2000 Mustang GT
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Re: would a clogged heater core make a engine overheat

Coolant should be 2 inches below the base of the overflow tank. Search on the forums for headgaskets, educate yourself, then freak out.
 

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1994 Deville
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Discussion Starter #6
:crybaby: ok i have a 94 deville and we have changed the radiator cap,the radiator the themostat and the water pump belt and for some reason now when we let it sit we can let it sit fior an hour it wont overheat now the problem b efore was thatthe water pumpbelt was so old i think it was slipping when i was driving but now thats fixed but now on the dash after about 45 min of driving it will say engine hott on the dash! iam totally lost and need help...i dont know what i can do to test and see if i have a bad head gasket or a cracked head i dont know what to do? or what my next step would be?but i mean now sience i put the belt on i mean theres ben no water boiling everything flowing good!

could the water pump be bad? i tunred it with my hands and it was real easy and smooth and i was told if it was it was ok!!! i just would liek to know what i could do to test the heads and the gasket if there is sucha a thing or if you have a better idea what to do please let me know!:crybaby:
 

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1994 Deville
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169 Posts
Discussion Starter #7
how can i test to find out if my head gasket is bad? my car is just overheating i changed the water pump belt the rad,rad cap,themostat and its still overheating so i dont know what to do what to do next or what to test and i wanna test the headgasket but i dont know how if anyone has any ideas for me please share! thank you!
 

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White Diamond '03 DHS (with DTS floor shift)
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Re: would a clogged heater core make a engine overheat

would a clogged heater core make a engine overheat? we seem to be overheating or running hot. trying to narrow this down.
1994 concours N*
NO.

its hard to get all the air out of the system.
The system is self purging. Check the purge line to be sure it is not clogged. That could explain your lack of heat and overheating. Do a search for purge line. Been discussed many times.
Check the belt tensioner to be sure that it is not rusted at the fulcrum and not providing enough belt tension.

A cylinder pressure test is the sure way to test for a bad head gasket, but don't jump to conclusions till you check the purge line & tensioner.
 

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Re: 94 Deville Conorse Over heating problem????

You are going to have a hard time getting anyone to follow this having 3 threads going on the same subject. I answered in the other one.
 

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1994 Deville
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Discussion Starter #11
iam sorry for haveibng 2 threads going on iam sorry this is the son my dads sleeping its my deville yea we chnaged alot of things but like i said before the water was boilding alot and then we looked atthe belt and the water pump belt was so britle i could bend it and it would fall apart i changed it and now it seems liek everythign was flowing right! but i drove it and then it came up with engine hot and i turned it off sat for 5 min and then went home and it didnt come back on.....i dont know what it could be or what my next move should be!
 

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1994 Deville
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Discussion Starter #12
THANK YOU RANGER! THANKS FOR ALL THE HELP YOUR GIVING ME I APERCIATE IT ALOT!


so i should check the purge line? and see if its clogged? this is the son once again i drive the ca..i was going to take it in and have someone just over look it and see if they see anything thats wrong i brought it in for a presure test and it came back good! like i said when i drive it its liek its ok for about 30 min maybe and then i will get on a 45 mph road put it on cruise controll and then it will come up on the dash saying either coolant hott,coolant low which i havent seen lately or engine hott my dads sleeping right now but you said the system is self purgeing...if you dont mind what does that mean and what is the purge line for? if u dont want to explain its alright! i just really hope its not a head gasket i hope!
 

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White Diamond '03 DHS (with DTS floor shift)
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Self purging means just that. No need to purge the air out of the system after a coolant change. It does it itself. The purge line is the 3/8" line that runs from the water pump housing to the surge tank. with the engine coldand at idle, pull the line off the surge tank. Coolant should spit or flow. out. Flow should increase with RPM. If there is flow, quickly plug it back on. If not, shut down, locate and clear the blockage.
 

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1994 Deville
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Discussion Starter #14
ok thanks alot i will do that and then i will get back to you! i think you were the same person we use to talk to when i first got my deville and you have been a big help to me thanks alot and sorry for making alot of threads i just have so many questions about it and thought if it was different topics to make different threads but iam thankful for your help and input!
 

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1994 Deville
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Discussion Starter #15
so the perge line goes from the water pump to what? i have the book for my car infront of me and iam trying to find the section on it but it goes from the water pump to what?
 

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1994 Deville
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Discussion Starter #16
iam so sorry but the surge tank is the tank that you put antifreeze in and water in right? iam sorry if it sounds a dumb question but iam not really familar with everything iam sorry! and its the guys son so just letting you know so if my dad comes on you dont think its him asking the questions lol sorry ranger!
 

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1994 Deville
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Discussion Starter #17
i took off the purge line from the surge tanka nd the flow was weak...do you think my water pump is bad? and if so how can i check it? when i changed the blet on it i was todl if you can spin the pully with your hand its smooth and easy its ok but thats info from advnace auto parts and i ddi that and it was easy to spin it..when i had the purge line off the flow was really weak! what do you suggest now?
 

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White Diamond '03 DHS (with DTS floor shift)
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Weak flow is normal at idle. As long as there is flow, the line is clear. Pump will usually leak when bad. I'd get the coolant tested for exhaust gases or do a cylinder pressure test at this point. That will confirm or rule out head gaskets.
 

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1994 Deville
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Discussion Starter #19
ok i guess i will call up some places tommorrow and see if i can bring it in for those test! just saying if its a head gasket do you think its worth to fix? and if so how much do you think it would cost for a head gasket fix? i was thinking if it was a head gasket fix just to get a new motor put in? but also thats a ify thing cause you dont know if that motor has any problems!
 

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White Diamond '03 DHS (with DTS floor shift)
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Head gasket repair is expensive. $3000 - $4000 because the drivetrain has to be removed. If you have it done, be sure that all 20 bolt holes get Timeserted. Whether it is worth fixing is a decision only you can make.
 
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