andyseldo Posted June 24, 2007 Report Share Posted June 24, 2007 I have recently had a problem with the coolant temp. The engine runs hot, but the radiator feels cooler than the engine. I was told the head gastet is blown. We found several problems, the A/C blower is not working, we also found a 30A fuse in the trunk fuse block blown. We can get the cooling fans to work if we engage the A/C, but the blower motor is shot and we were told not to run the A/C without blower motor. If we leave the radiator cap off and start the engine after 10-15 min the water starts to boil out the coolant tank. Questions: Where can we obtain an electrical schematic or CD repair manual, has anyone had this problem, or can give any guidence we would appreicate it Caddybound Link to comment Share on other sites More sharing options...
Bruce Nunnally Posted June 24, 2007 Report Share Posted June 24, 2007 The factory shop manuals are published by Helms, Inc http://www.helminc.com and include schematics. They can often be found at a discount on ebay; the new ones are $125 or so per set. You should try a exhaust gas detection kit first, such as http://www.napaonline.com/masterpages/NOLM...2f+Engine+Block Around $50. It is used to detect exhaust gases in the cooling system. More info: http://www.arrowheadradiator.com/head_gask...n_leak_test.htm Another approach is to use a custom fitting and shop air with the engine off to blow air into individual cylinders and monitor the overflow for bubbles. Bruce 2023 Cadillac CT4-V Blackwing Follow me on: Twitter Instagram Youtube Link to comment Share on other sites More sharing options...
JimD Posted June 24, 2007 Report Share Posted June 24, 2007 I have recently had a problem with the coolant temp. The engine runs hot, but the radiator feels cooler than the engine.Are you 'feeling' the radiator temperature from the engine side of the radiator? If you are trying to assess the radiator temperature from the front of the radiator, you could be 'feeling' the A/C condenser coil and if the A/C is OFF, the condenser coil will not be hot. I was told the head gastet is blown.There are a number of checks to be made before diagnosing any engine as having failed head gaskets. Unless those steps have been taken, no one can tell you for certain that a head gasket has failed or not failed. We found several problems, the A/C blower is not working, we also found a 30A fuse in the trunk fuse block blown. We can get the cooling fans to work if we engage the A/C, but the blower motor is shot and we were told not to run the A/C without blower motor.The cooling fans should come on at low speed when the coolant temperature reaches something like 223 degrees F with the pressure cap securely installed and the A/C controls OFF. If you do not see the fans spinning as the coolant temperature starts to climb, the fan circuitry would be the first item to investigate. You can test this in your driveway on a warm day with the engine at idle.If we leave the radiator cap off and start the engine after 10-15 min the water starts to boil out the coolant tank.The problem with idling the engine with the pressure cap removed is you have lowered the boiling point of the coolant. Depending on the concentration of your coolant, at zero pressure, the boiling point will fall between 223 degrees and 212 degrees F. See above for temperature at which the fans should come on. Operating an engine like the Northstar with the cooling system pressure cap removed is setting yourself up for a scalding. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
zonie77 Posted June 25, 2007 Report Share Posted June 25, 2007 Bad HG's are a possibility. Before you go off replacing things have a coolant exhaust gas test done. Either do it yourself, as Caddyinfo suggested, or take it to a radiator shop. Radiator shops do it much cheaper and quicker than a regular mechanic. There are plenty of threads about doing HG's on a Northstar. Since it's a fairly large engine it is very difficult to do it in the car. The easiest is to drop the cradle out the bottom and then it is very easy to replace the HG's. If you do it yourself it's anywhere from $300-$800 for parts (depending on how many gaskets etc you decide to replace) and $200-400 for the timesert kit to repair the head bolt threads that are probably stripped. The low estimate is for a used kit that you could resell so it would be $50 for the inserts. For a start look at the thread on "Reducing the cost of HG replacement" Also, everything JimD said is accurate. Link to comment Share on other sites More sharing options...
STSgirl96 Posted October 17, 2007 Report Share Posted October 17, 2007 Hi I have a 1996 STS with the 4.6L V8 Northstar. She has 164,580 miles. I kinda have the same problem as Caddybound. We were loosing coolant and she was starting to overheat but not to the point of overheating in the red. We found the radiator was bad and we replace. Thought we had the overheating problem fixed but she is starting to overheat again. We have been reading everyones posts and can't tell you how thankful and happy to have this forum to refer too!!! We have let her idle and noticed the fans are NOT working at all. So we turned the a/c on and they still do not run. What places should we look to to find out why? Also my traction control light and ABS light will not go off now. Can I safely drive the car like this? I keep reading about head gasket failure....I have some white smoke coming out of the exhaust when I first start it up...noticed that today when I started it and run into house and came back out. I also have to keep cleaning my exhaust tips....they are constantly building up with black soot. Any help and suggestions would be most helpful. Barbie Link to comment Share on other sites More sharing options...
Ranger Posted October 17, 2007 Report Share Posted October 17, 2007 Barbie, Is it "smoke" or steam from the pipes? Go back and take a good whiff of it. If it smells like coolant, your head gaskets are shot. If it smells like fuel, it mat be a bad FPR. As for the fans, check the relays and pull the DTC's. The DTC's will also tell you what is causing the ABC/TC lights to be on. Yes, you can drive it safely. The lights mean that the ABS & TC is inop. Just like driving a car with no ABS or TC installed. Link to comment Share on other sites More sharing options...
STSgirl96 Posted October 21, 2007 Report Share Posted October 21, 2007 Hey Ranger! Ok. I checked today and there was nothing coming out of tailpipes. But it does smell like fuel. I will pull the DTC's and will check the relays. I appreciate your quick answer. ~Barbie Girl~ Link to comment Share on other sites More sharing options...
rmac-etc Posted October 21, 2007 Report Share Posted October 21, 2007 If the fans are not working when the appropriate engine temp happens that is JOB ONE. The engine will get hot if the fans aren't doing their job (unless you are in constant motion).. Make sure that the fuse for the fans is ok first, if so then figure out why they aren't working. I had a perfectly good engine, radiator, coolant level, etc but the fuse for the fan was not in the right spot (my fault), so during stop and go city driving the fans did not come on and I got the engine too hot message (>252 degrees) and it went into 4 cylinder survival mode... just because the fans were not functional.... and yes the engine protected itself and is still in great shape 5-6 years and many miles later.... hope your issue no more than that ... (95 etc, 160K mi) Link to comment Share on other sites More sharing options...
Texas Jim Posted October 21, 2007 Report Share Posted October 21, 2007 Hey Ranger! Ok. I checked today and there was nothing coming out of tailpipes. But it does smell like fuel. I will pull the DTC's and will check the relays. I appreciate your quick answer. ~Barbie Girl~ Barbie, In an earlier post you also mentioned that you had to constantly clean the exhaust tips. You stated that the service emmisions code is set. That statement and this one leads me to believe that your mixture is running extremely RICH. If that is the case, it may be your FPR leaking. I think that would cause it to run rich which would set the emmisions service code, cause the exhaust tips to get dirty and let you smell fuel in the exhaust. Pull the vacumn hose going to the fuel pressure regulator (FPR). There should be NO FUEL leaking from the vacumn connection. Link to comment Share on other sites More sharing options...
Ranger Posted October 21, 2007 Report Share Posted October 21, 2007 Yeah, I'm with Tex. Check that FPR. Highly suspicious. Link to comment Share on other sites More sharing options...
KHE Posted October 23, 2007 Report Share Posted October 23, 2007 Just to add - when checking the FPR for fuel leakage, look at the nipple on the FPR when the vacuum line is disconnected. The other suspect may be a leaking injector. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
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