Tan, Before you do those steps,
#1. Start engine with engine being cold, check for pressure on coolant system to verify head gasket is OK. A bad head gasket will pump air into the coolant. This air will often get caught between water and thermostat and basically insulate thermostat such that it never gets warm enough to open. This is the same thing that happens when you fill system and have to "burp" it. BTW the best way I have found to burp coolant system is to start engine and let it idle while watching temp gauge. When gauge get just slightly hotter than "normal" turn engine off. Go get a soda pop and let it burp, after it burps there should be little pressure on upper hose. Top off system and it is usually OK. Sometimes this has to be done twice, but not often. Trampas -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tan Qu Sent: Thursday, December 29, 2005 5:35 PM To: Mercedes Discussion List Subject: Re: [MBZ] SOS - '87 190Dt Overheat! -update Well, we have a lot good insight here. So here is what my plan is: 1. Remove the 2-piece fan shroud 2. Remove thermostat and bolt the thermostat housing back 3. Remove upper hose and overflow tank cap and fill the engine and radiator. 4. Close overflow tank cap 5. Start the engine 6. If coolant comes out the engine madly, pump is ok. Put back the upper hose 7. Let engine continue running with various speed. keep an eye on the temp gauge. 8. Turn off the engine. Hand check the radiator surface to see if there is any cold spot. 9. If all check out OK, I am out of ideas again. Tan --- Jim Cathey <[EMAIL PROTECTED]> wrote: > > I don't have an infared temp meter so I have to > come > > up with something else to get the block temp. > > Harbor Freight has them on sale periodically for > $50. > Mighty handy. > > > Now, if the pump is ok, water should come out the > > upper radiator hose even with thermostat in, > right? > > Que? Flow direction is from top to bottom, and the > thermostat is in series with the top hose to the > radiator. Trampas' advice is good. > > If you insist in replacing the pump and it doesn't > help, be prepared for some ribbing! It _could_ be > bad, but it's highly unlikely. We will apologize > profusely if it _is_ bad, and say "Huh. One for > the books." > > > How likely is that the temp sensor is bad? Where > is > > It happens quite a lot, actually. I'm surprised we > all > forgot to recommend an independent test of the gauge > temperature. > > > the sensor located that is connected to the gauge? > I > > know there is one right below the thermostat > housing > > and one near the upper radiator hose. I actually > > disconnected both both the gauge still registered > > 120C. Is there a third temp sensor that I don't > know > > of? > > Look on the side of the head near the middle. Might > be kind of buried. > > -- Jim > > > _______________________________________ > http://www.striplin.net > For new parts see official list sponsor: > http://www.buymbparts.com/ > For used parts email [EMAIL PROTECTED] > > To Unsubscribe or change delivery options go to: > http://striplin.net/mailman/listinfo/mercedes_striplin.net > _______________________________________ http://www.striplin.net For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://striplin.net/mailman/listinfo/mercedes_striplin.net
