My car is running warmer than normal?

1999 DODGE INTREPID

91,000 MILES • 2.7L • AUTOMATIC

ALLAN36

MEMBER
1 POST

My 1999 Dodge Intrepid has a rebuilt engine in it, from the previous owner.

My temperature gauge is sometimes running warmer than normal. It is not overheating.
I don't see any leaks. I added about a 1/2 gallon of coolant recently. I bought the car
used and the coolant may not have been changed for 2 or even 3 years or longer.

The car is fine and drives well most of the time, but after a driving about 12 or 15 miles the gauge will
go up to about 1/2 way. It used to be about 30 percent. Also during stop and go driving, it is running warmer. About 1/2 way on the gauge.

I took it to a mechanic who test drove the car and initially did NOT find a problem.
He did some more testing and said the fans are coming on, the coolant is at 70%
efficiency. He said the thermostat is okay. There are no leaks. So he kinda said, it's "likely" the water pump.

He said he put it on a "scope". Another mechanic told me there is no diagnostic for a water pump.

Unfortunately, because the water pump is internal, the repair cost is very high. He quoted $2200.
That is probably what the car is worth. I feel a little worried, that he misdiagnosed the car or is maybe trying to cheat me with an expensive repair, that is not needed.

But I want the car to run well and not overheat and damage the engine.

What do you think I should do? Get another diagnostic from a different mechanic? Continue driving the car since it seems okay? Are there other things to check on the car? And since it's summer, is it possible that the car is just running warmer than normal due to temperatures of about 90-95 in Denver, where I live?

Thank you,
Allan

Jul 9, 2026 at 3:24 PM

CARADIODOC

✓ASE Certified Mechanic
34,321 POSTS

Absolutely it will run hotter in summer. I see that on my Ram and Caravan too. I'm in Wisconsin.

Interestingly, I visited a business in Denver in 1999. I was driving an '88 Grand Caravan with over 400,000 miles. At that time, it had gradually developed a similar problem where it ran rather warm at anything over 60 mph or over 60 degrees outside. Cooled back down if I turned on the rear heater fan. The problem was about a quarter of the radiator's cooling fins had corroded so badly, they crumbled like a rotten chocolate chip cookie when touched. The radiator simply wasn't able to give up its heat to the surrounding air fast enough.

I have a suspicion, the "scope" the first mechanic was referring to was a scanner to view live data from the Engine Computer. Among the dozens of data items, it will display coolant temperature, and the corresponding signal voltage from the coolant temperature sensor, (CTS). Older vehicles had two of them; one for the dash gauge, and a more precise one for the Engine Computer. By '99 the dash got its information from the Engine Computer, so they just needed one sensor.

The Engine Computer turns the radiator fan on at 212 degrees, and off, as I recall, at around 198 degrees. It rarely turns on at highway speed because natural air flow is more than sufficient. You're more likely to hear the fan come on gradually and ramp up speed in city driving on hot days.

If you want to verify proper operation yourself, many of the newer inexpensive fault code readers can also display that live data, although on most, the numbers update painfully slowly, as in perhaps once every four or five seconds. That's fine for your needs. Professional scanners update a few times per second, but cost a few thousand dollars. The code readers I see advertised cost in the area of $30.00 to $100.00. For '96 through most '03 models, you need a reader listed for "OBD2" systems. That's the "on-board diagnostics, version 2, emissions system. That will show a more accurate reading than that on he dash gauge.

Jul 10, 2026 at 12:17 AM

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