94 running hot!?????
Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds / (Old System)

Cadillac Technical Archive | Cadillac Dealers | Cadillac Reviews | Cadillac Dealer Reviews | Cadillac Vendors

CadillacForums.com is the premier Cadillac Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Results 1 to 13 of 13
Northstar Engines and System Technical Discussion Discussion, 94 running hot!????? in Cadillac Engine Technical Discussion; hello i have a 94 eldorado, i just got it and it was overheating and going into limp mode when ...
  1. #1
    ttpost is offline Cadillac Owners Member
    Join Date
    Sep 2005
    Posts
    12

    Angry 94 running hot!?????

    hello i have a 94 eldorado, i just got it and it was overheating and going into limp mode when i got it. the previous owners had just replaced the radiator and hoses, the fans are working. i checked the thermostat and it didnt seem to be opening and looked like it had gotten hot. when i did that it was showing about 240 on the temp guage. when i drained the water within a few minutes i put a temp gauge in it and it showed about 150?. i replaced the thermostat and had the same problem. the next thing i did was changed the sending unit, thinking it was faulty, still showed to be running hot. i pulled the water pump cover and checked it, the impellar looks fine and the bearings seem to be ok. while i was at it i pulled the thermostat and cut out the old one and put it in, in other words no thermostat. now it runs about 215 on the freeway, and about 230 at idle. i also replaced the radiator cap. the heater blows hot air at all times. my thoughts are either the water pump belt or the water pump is not moving enough volume. i have inspected the belt and it seems ok and the tensioner seems to be ok too. also i checked the purge line and it is working fine. any and all suggestions would be appreciated.

  2. Remove Advertisements
    CadillacForums.com
    Advertisements
     

  3. #2
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
    Automobile(s): White Diamond '03 DHS (with floor shift)
    Join Date
    Jun 2004
    Location
    Woodstock Ill.
    Age
    66
    Posts
    70,478

    Re: 94 running hot!?????

    Sounds like you've checked all the cheap and easy things. On to the head gaskets. Pressurize the cylinders and watch for bubbles in the surge tank.

  4. #3
    ttpost is offline Cadillac Owners Member
    Join Date
    Sep 2005
    Posts
    12

    Re: 94 running hot!?????

    how much pressure should there be at purge line? it seemed to have low pressure. i just pumped some water into a coffe can to take a temp reading and it shows about 150, the dash gauge showed 225. also with the thermostat out it doesnt overheat, i ran it about ten miles and it ran fine at about 210. could it be another bad sending unit? head gasket is last ditch effort, if it needs to be done.

  5. #4
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
    Automobile(s): White Diamond '03 DHS (with floor shift)
    Join Date
    Jun 2004
    Location
    Woodstock Ill.
    Age
    66
    Posts
    70,478

    Re: 94 running hot!?????

    Flow out of the purge line is low flow. The main thing is that it does flow. Removing the thermostat is just a band aid and will likely get worse if the problem is not found and fixed. Your coolant tempuratures differ because they are taken from different locations. There is only one coolant tempurature sending unit.

  6. #5
    ttpost is offline Cadillac Owners Member
    Join Date
    Sep 2005
    Posts
    12

    Re: 94 running hot!?????

    i just took the temperature within 30 seconds after i shut the engine off. i pressurized the system and took a temperature test with the water out of the purge line, it was 195 the dash gauge said 250. several times the dash gauge would be reading 225 to 230 and then it would all of a sudden drop to 199 or 200 then a few seconds later it would jump back up. i pressurized the radiator and ran it for awhile and the pressure didnt increase or decrease and that was running for about 10 minutes. i am still concerned that either i have a faulty sending unit or one of the wires is shorting out to the gauge.the last test i will run in a pressure test on the cylinders and check for air bubbles. i really appreciate all your advice thanks. i am a decent mechanic as a hobby, but i am not familiar with these motors thanks again.

  7. #6
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
    Automobile(s): White Diamond '03 DHS (with floor shift)
    Join Date
    Jun 2004
    Location
    Woodstock Ill.
    Age
    66
    Posts
    70,478

    Re: 94 running hot!?????

    Again, you are taking a reading at the purge line out put and the temp sensor is on the rear of the head. That may acount for the different readings. 224 I believe is when the cooling fans turn on. 229 or 230 is when they go to hi speed. That may explain the drop at that point and might confirm that the temp sesnor is indeed correct.

  8. #7
    oldgamer's Avatar
    oldgamer is offline Cadillac Owners Enthusiast
    Join Date
    Feb 2004
    Location
    Staten Island, NY
    Posts
    577

    Re: 94 running hot!?????

    Quote Originally Posted by ttpost
    i just took the temperature within 30 seconds after i shut the engine off. i pressurized the system and took a temperature test with the water out of the purge line, it was 195 the dash gauge said 250. several times the dash gauge would be reading 225 to 230 and then it would all of a sudden drop to 199 or 200 then a few seconds later it would jump back up. i pressurized the radiator and ran it for awhile and the pressure didnt increase or decrease and that was running for about 10 minutes. i am still concerned that either i have a faulty sending unit or one of the wires is shorting out to the gauge.the last test i will run in a pressure test on the cylinders and check for air bubbles. i really appreciate all your advice thanks. i am a decent mechanic as a hobby, but i am not familiar with these motors thanks again.
    If you noticed sudden temperature jumps that don't look real, I mean they look like a gauge problem (temperature readings jump up and down very fast, less than a second) it possible computer problem. I found already 3 or 4 cars with that problem and all of them were 94. If you noticed these jumps happened only after temperature riched more than ~50C or happened only before 50C it is defenetaly computer. How it looks like? What about loosing coolant?

  9. #8
    ttpost is offline Cadillac Owners Member
    Join Date
    Sep 2005
    Posts
    12

    Re: 94 running hot!?????

    not losing coolant at all, i am going to hook up a mechanical gauge at the head and see what happens, that will give me an answer. there is almost a 50 degree difference between what the dash gauge shows and what a physical test of the water temp shows, and the delay between testing this and shutting the motor off is app. 30 seconds.i can undestand a difference in the readings but 50 degrees? if the mechanical gauge shows up as accurate with the electrical gauge, then i will move on to checking the head gasket. do these motors usually run great even with a blown head gasket? i just want to be positive before i start tearing it down thanks for your advice guys

  10. #9
    oldgamer's Avatar
    oldgamer is offline Cadillac Owners Enthusiast
    Join Date
    Feb 2004
    Location
    Staten Island, NY
    Posts
    577

    Re: 94 running hot!?????

    Quote Originally Posted by ttpost
    not losing coolant at all, i am going to hook up a mechanical gauge at the head and see what happens, that will give me an answer. there is almost a 50 degree difference between what the dash gauge shows and what a physical test of the water temp shows, and the delay between testing this and shutting the motor off is app. 30 seconds.i can undestand a difference in the readings but 50 degrees? if the mechanical gauge shows up as accurate with the electrical gauge, then i will move on to checking the head gasket. do these motors usually run great even with a blown head gasket? i just want to be positive before i start tearing it down thanks for your advice guys
    I hope it's not a gasket problem, cause you don't loos a coolant at all. Don't relay on phisical test a lot. To make it right you should applay temperature gauge tight in place on a block closest to temperature sensor, which is hard.
    50 degree difference between a drained water and block temperature is not much. When you drain temperature sensor still shows you actual block temperature, not actual water temperature. And drained water get colder pretty fast when it move through all hoses. What about temperature jumping, how fast it jumps? That should be a key. If it jumps too fast, faster than a second, it looks like computer problem or short/dirt between sensor wires.

  11. #10
    ttpost is offline Cadillac Owners Member
    Join Date
    Sep 2005
    Posts
    12

    Re: 94 running hot!?????

    the temperature jumps within a second it jumps anywhere between 10 degrees and as much as 30, it is pretty random when it jumps sometimes several times in a minute and other times it doesnt jump at all. doesnt seem to change with engine movement though. thanks

  12. #11
    ttpost is offline Cadillac Owners Member
    Join Date
    Sep 2005
    Posts
    12

    Re: 94 running hot!?????

    just noticed something, as i stated before the car had a new radiator installed before i bought it, after doing some reading on here i noticed something about not using green radiator fluid and also about adding supplements, could this be the cause of my overheating. it has green radiator fluid in it and i doubt if they used any supplements. i am not sure what the difference is in the fluids but it seems to be cruicial from what i have read. is the difference in the fluid for cooling or corrosion or both thanks

  13. #12
    cl1986's Avatar
    cl1986 is offline Cadillac Owners Connoisseur
    Automobile(s): 94 Eldorado, 94 SLS got crushed
    Join Date
    Jun 2003
    Location
    South Dakota
    Age
    35
    Posts
    1,485

    Re: 94 running hot!?????

    Funny thing is, these cars run great with bad headgaskets.

    i answered your last question on your new post.

  14. #13
    oldgamer's Avatar
    oldgamer is offline Cadillac Owners Enthusiast
    Join Date
    Feb 2004
    Location
    Staten Island, NY
    Posts
    577

    Re: 94 running hot!?????

    ttpost,
    Let separate the problems:
    How you know that engine is overheating? You have temperature gauge jumps, so it doesn't mean that engine overheats. The temperature just can't jump 30 degrees so fast. Check the codes. If temperature readings jumps computer should through a code related to the sensor. It's can be bad wiring or computer. In my case I changed computer (found used on internet for $50) and problem was solved. As I told I found other 3 owners with the same computer problem. All of us have 94. But it can be short/dirt between the wires too. Try to locate at first.
    You can do simple experiment: with sensor disconnected readings should be -40F or even "-". Anything else will confirm bad wiring or computer problem.

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.
If you do not want to register, fill this field only and the name will be used as user name for your post.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Bookmarks

Cadillac Posting Rules

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
Read about Lincoln | Buick | Kia Forte Forum
Need products for your Cadillac? Check out your options at the links below:

custom floor mats | Cadillac Chrome and Black Chrome Wheels | window tinting