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Q: Car Runs HOT! on 1997 Mazda Millenia

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My car keeps running out. I have had a friend of mine that is a cert mechanic work on it. He has checked timeing belt, water pump, t-stat, fans are working, and all the sensors have been replaced and double checked to make they are good and it still wants to run hot. I have ran some radiator flush in it for a few days then drained and refilled my radiator to clean the radiator incase it was clogged (that I did on my own). He tested it for a blown head gasket and it doesn't have one. He is now saying that the only other thing he can think of that could be causing it to run hot is if the computer has gone bad. I checked pull-a-parts and a computer runs for only about $25. But I have ran out of money to waste and need my car to get back and forth to work. Does the computer sound like it could be the problem? or maybe some other suggestions???
My car will run for about 20 miles fine then it will start to run hot. Doesn't matter if I am sitting or moving. I have to pull over and let it cool down. Please help! Thank you!
No car image 94a1663db56199c5353592009e34aaa51078a2469bed068bb8d6f0ba43accf97
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I agree with Bret, verify the running temperature is actually what is being indicated on the gauge. Is the car "loosing coolant" is it boiling over? More likely the radiator is restricted than a computer issue. I presume the thermostat has been changed. I know these engines are expensive to work on. A friend of mine has two of them. I haven't heard of the water pumps having problems on these engines but some cars with plastic water pump impellers have impeller failures. The most accurate way to test for a blown head gasket on a gasoline engine is to test for the presence of carbon monoxide in the cooling system. Snap-On, Matco (part # CO 2000), and Napa sell a tool to check to carry out this test. Another link to a supplier of this tool is Carbon Monoxide is only present if there is a blown head gasket or cracked cylinder head. I think the napa part number 700-1006. . Signs of a blown head gasket are coolant loss (frequently have to top up the coolant level of the engine without seeing an obvious leak), experiencing over heating or rough engine running or the presence of white sweet smelling steam from the exhaust. A badly blown head gasket may allow engine coolant and oil to mix.
Bret would you consider being my future ex-husband ? No ? how bout just my mechanical love interest ? Seriously man .....I am done stick a FORK IN ME and a pitchfork in my 97 millinia. My best friend has worked for weeks on what can only be called a hardship case ..ME and my " Millie "... Had it since 97 kept it up pretty well, sacrificing nails and tanning sessions if that tells you who came first..She's been a soldier of a car, never left me stranded on the highway.. may have towed her from home to shop but she got me home !! Soldier I tell u. Can't figure why she still hot .Going to check out prices on the monoxide detector tool. hopefully won't require my first born !! Thanks.. LoosingitLyndaLou in Atl
One thing you need to be sure of is if the engine is actually running hot. This could be an issue with the temperature sensor, wiring or temperature gauge. Have your mechanic use a thermal temperature tool to measure the engine temperature when the gauge reads hot, see if the actual temperature matches what the gauge says.
Thanks for your help. I did end up barrowing an infrared thermometer to check the temp of my motor when it is saying that it is running hot. The top of my motor said it was about 190º (which is where I was told it is supposed to be) but the bottom of my motor said it was about 300º. I wasn't sure which temp to pay atten to. I was also told by another mechanic to replace radiator hoses if they are old and then if that didn't help take my car to a shop that can flush the whole system out (instead of just cleaning the radiator). So I guess I am going to try these things and see if they help.
Radiator hoses will not cause this problem, so even if they're in poor condition I wouldn't replace them until the original overheating issue has been addressed.
You will have to actually see if the engine is actually running hot. A check with a thermal laser gauge and also checking the on-board computer to read what it sees will at least verify the overheat. If all components are in fact working as designed, then I would put my thoughts on a new radiator. If any of the passages are restricted you will have such a problem. Simply flushing will not cure your problem. There have been known problems with waterpump impellers becoming loose or broken on certain models. Plastic impellers especially are problematic.
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