C-NOTE Posted October 16, 2008 Report Share Posted October 16, 2008 I have never sent out a post before so if I am doing something wrong please let me know. My 2000 deville 4.6 N* run hot when I turn on the A/C, without the A/C on I can do the WOT but as soon as I turn it on it starts to run hot, What is causing this problem?, I need help PLEASE?????????? Link to comment Share on other sites More sharing options...
Ed Hall Posted October 16, 2008 Report Share Posted October 16, 2008 Here is a list of things to check: 1) Is the engine in fact overheating?, or are you freaking out from the digital dash or analog gage, know the norms! 1a) check coolant level 1b) check coolant concentration, must be at least 50/50, can go up to 70/30 for higher boiling and lower freezing temps 2) check water pump belt and tensioner 3) pull purge line and check for coolant flow, before replacing hose check tank surge nipple for clog 4) check cooling fan operation, AC off, fans on at 228 off at 217 (plus or minus) 5) check cooling fan operation, AC ON, cooling fans on full time 6) check thermostat, if it has not been replaced, replace 7) check cap, if it has not been replaced, replace 8) pressure test system look for leaks at hose clamps, heater pipes, radiator tanks, surge tank, water pump 9) check for debris blocking radiator, check for proper air deflector location 10) if all of above items check out, have coolant checked for combustion by products (Napa sells a kit or some radiator shops do the test) Link to comment Share on other sites More sharing options...
Cadillac Jim Posted October 16, 2008 Report Share Posted October 16, 2008 It sounds like a cooling fan fuse, relay, connector, or motor to me. A quick check is to start the engine cold and turn the A/C on. Both fans should run at low speed. If not, there is a problem with them. If they both are on, run the OBD codes and post them here. here's how: http://www.caddyinfo.com/readingcodes.html You can do this as a first step in the checklist process recommended by Ed Hall, which is excellent. Stay with us as you work this problem. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
C-NOTE Posted October 16, 2008 Author Report Share Posted October 16, 2008 I just put a new radiator in last week, it had cracked and ran hot, cat convertor was clogged, changed water pump, belt and tensioner, new radiator cap and Thermostat......I will pull the codes and post them....I am not a mechanic so when you say the surge tank is that the same as the reservoir tank??? Link to comment Share on other sites More sharing options...
C-NOTE Posted October 16, 2008 Author Report Share Posted October 16, 2008 Oh and by the way Thank you guys for all this help and thanks for the Welcome to CADDYINFO....l Link to comment Share on other sites More sharing options...
Ranger Posted October 16, 2008 Report Share Posted October 16, 2008 On the Northstar, it is a surge tank, not a reservoir. It is actually a pressurized tank that is part of the cooling system. See #3 in Ed's post. The purge line is the 3/8" line on the side of the surge tank near the top. Pull it with the engine idling (cold). There should be coolant flow. Is there? If so, quickly plug it back on. If not, locate and clear the blockage. This line, as its name implies, purges air from the sytem and if clogged will cause an overheat situation. Link to comment Share on other sites More sharing options...
C-NOTE Posted October 16, 2008 Author Report Share Posted October 16, 2008 Ok, so that is the Black and white tank that sits on the passenger side in the corner, right? Link to comment Share on other sites More sharing options...
Ranger Posted October 16, 2008 Report Share Posted October 16, 2008 They seem to move it around , but yeah I think that is where it is. Link to comment Share on other sites More sharing options...
C-NOTE Posted October 16, 2008 Author Report Share Posted October 16, 2008 Ok, thanks Ranger, after it cools down a bit I will try that and let you guys know what happens....... Link to comment Share on other sites More sharing options...
C-NOTE Posted August 10, 2009 Author Report Share Posted August 10, 2009 Hey I just wanted to thank all you guys again for the help with my car......The problem was a line (hose) between the engine and the firewall it was leaking just enough to make it run hot....You can't see it because it is way in the back, it will leak but will burn off on the engine....A mechanic says that a lot of people junk their cars for this $20 piece. The CADDY is back on the road and doing well....Thanks GUYS!!!! Link to comment Share on other sites More sharing options...
Texas Jim Posted August 10, 2009 Report Share Posted August 10, 2009 Thank you for the update. We always like hearing what the final outcome of a problem is. Link to comment Share on other sites More sharing options...
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