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Chrysler 300M Overheating mystery



  • gking101gking101 Posts: 1
    I can use the Cd. Email me at
  • littleearllittleearl Posts: 1
    I see you have offered the entire collection of Chrysler Service Technician Manuals , which are over 10,000 pages (on CD only) , for the 2002-2004 300M's / Intrepids and Concorde vehicles - FREE on your Edmund's post.

    I am very interested in these as I am starting to need more in-depth instruction on repairs for my 2002 300M. Could you please send me these? Thanks so very much!
  • Due to forum abusers (who will not even refund me any postage) , the only
    way to get the CD , is to send $6 to my Paypal address : - so that I can pay the postage (while the CD's contents are still FREE). If you send $6 , be sure to also send me an email at the same email adress , so that I will send the disk to the address you want it to be sent to. The manuals are authentic Chrysler (not altered or reprinted etc. manuals). Worth alot more than $6. I have sent about 60 of these in the last 2 years. It's a no-brainer .
  • bookiettbookiett Posts: 1
    I recently changed the radiator thermostat fan fan relay switch belt and the engine isn't getting hot and the internal cage is only going up to half mark but the water/antifreeze in the resevior is bubbling or should say boiling then steaming out.. Any ideas??
  • pitmanoeuvrepitmanoeuvre Posts: 68
    edited July 2013
    If your engine temperatures are normal , then you can assume the waterpump is OK , but you may have put the thermostat in backwards / causing the overflow reservoir to become a radiator. It is possible , that when you change a thermostat and follow how the thermostat is already installed (at which time you are also changing the thermostat because ? the engine is overheating?) , you will have repeated installing the thermostat incorrectly - if you match the direction that the thermostat is placed. Any time you change a thermostat you should be checking that the closed position is towards the engine - while the spring/open position is towards the radiator.

    In some cases boiling of the fluids indicates that the waterpump is not functioning , but your interior temperature gauge should show a maximum reading as well. Whenever there are conflicting symptoms or indications , it would be best to recheck the positioning of the thermostat in the housing. Boiling fluid in the reservoir indicates that the heated fluid has no heat outlet (radiator) , so the fluid keeps heating up until it boils. You should also be replacing the overflow reservoir cap because it is vented (@16lbs) , so if that cap's rubber seal or pressure spring is not working properly , you have no blow off (which , since it is boiling , should already be occurring).

    If nothing really makes sense , you should check that you are using a full fill of the correct coolant/antifreeze. With the all aluminum 3.5L engine , the service manual strongly requires that the "yellow" (not green) coolant is used at all times and not mixed (ever , unless it is an emergency). Aluminum engines , or even engines that only have aluminum heads , must use "ethylene glycol coolant " - as opposed to "polypropylene glycol coolant (which is green etc. for cast iron and steel engines only). Mixing these 2 is not acceptable according to the service manual for the 300M , and even if you do , you MUST flush and refill ASAP. Aluminum requires special protection , while all of the engine's other components and calibrations are set in accordance with ethylene glycol (IE : thermostat / gauge / radiator / hoses / heater etc).

    The last factor is the coolant mixture. I never buy 50/50 mix coolant , because I don't buy water , and those premixed containers are for immediate topups only. When you buy 100% coolant , you mix equal amounts of water in another container and fill from that (50/50). From there , you check the interior temperature gauge and adjust accordingly : if too hot , add coolant , if too cool , add water. Try to add 8 ounces at a time until the gauge balances just under half way. This can be a bit tricky too , when you don't really know if you have a 50/50 mix to work with. I always start by using the rule of thumb that "water" has a much lower boiling point than any coolant. From there , I know that the fluid will boil if there is too much water , or NO coolant at all - BUT , it is possible for coolant to boil as well. If you were to fill your vehicle with coolant only , once the coolant reaches it's higher than water boiling point , it will boil to where it will cool alot slower (take more time) than water. It can be a bit confusing to determine which way to go when you don't know about the actual fill. You can do so though , if you know that you can't run any engine strictly on water , as it will eventually overheat profusely. So... you could have either one of the 2 - too much coolant , or too much water.
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