Engine not getting up to temperature but heat in car is fine

Hi, I am hoping someone can help me out. My car recently had a coolant leak and was supposedly repaired… the mechanic stated he changed both thermostats as my car has 2. The “repair” was done just under a month ago… up until recently I was still smelling burning coolant even though they apparently washed off the components after the fact… last week or so haven’t smelt it nearly as much. Now my temperature gauge while my heat is on in car will not reach temperature… it sits at about a 1/4 on the temperature gauge. When the heat is off it will get to proper operating temp just slightly under halfway on gauge. This just started a few days ago. The top rad hose after running the car for a period is very hot to touch, I have not checked underneath the radiator hose.

I am not very well versed in mechanics at all. The reason I am asking for help in the right direction is I do work at a truck shop and may be able to repair myself with instruction via web etc or other mechanics around me. I was taken for a ride as I was charged $100 for the 2 thermostats only to find out he used cheap after market ones… I am just not entirely convinced it is a stuck open thermostat issue due to the fact that the heat in car still works perfectly fine.

Any advice would be greatly appreciated as this so called mechanic now wants to charge me an additional amount of money exceeding $50 for the difference of the warranty covered thermostats to original OEM ones which I was under the understanding for the price of parts alone was already installed. In total the repair was over $300 and now I have issues less than a month later and live on a tight budget as most do these days.

Thank you in advance for anyone that can help.

Best Regards,


I’d guess the problem is either the cooling system has a little air left in it from the prior repair and needs to be air bled again. Or one or both of the replacement thermostats are faulty or the wrong part number; i.e. opening at too low of temperature. Given the problem is noted only when the heat is on, I’d say the first is more likely, you need to have the cooling system bled of air again. If your Avenger is sort of a low slung race-car design, those can be quite difficult to bleed and require a special procedure be followed. in some vehicles special equipment is needed to air-bleed the cooling system. There was a poster with a truck here not long ago w/that problem.

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Your Avenger not only has 2 thermostats, but they are of different temperatures. Your car’s engine deliberately has no coolant passages between the block and head. The block is supposed to run hotter and the head cooler. This improves fuel mileage by not heating the air coming into the cylinders as much. The two systems have to be bled separately.

I would not worry about aftermarket vs oem thermostats. I have never purchased an oem thermostat and never had an aftermarket one fail.

Because you are still smelling coolant, you might have a small leak someplace, that will allow air in.

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??? Really !!

Thank you very much guys for the advice, I really appreciate it. Is there anywhere I can find this special bleeding procedure and how to bleed the block and head separately?

I can’t thank you all enough for taking the time to reply.

I hate to say it again but all of these special procedures and cautions are covered in the factory service manuals. Maybe Alldata too, I don’t know. Yes they are expensive but without them, the best bet is to take it to someone that knows. I try to buy them but not always and it can be a head scratcher when something unusual comes up.

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I kind of doubt it

I just looked at Chilton’s for the Dodge Avenger with the 2.4 liter engine, which seems to be the one with 2 thermostats . . . and there was absolutely no mention of a special procedure to bleed air

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Could it be a faulty relay or pcm issue? I have been missing my fuse cover for some time now. I will try to bleed it for sure as perhaps there is another minor coolant leak somewhere that is so small it’s not noticeable but side note my coolant resevoir has not dropped even the slightest in the month since repair. One thing also I should note is twice now I have seen white smoke coming from front of hood and when I open hood cannot locate where it is or even see it… I thought maybe snow got in and was burning off as I’m missing my skid plate underneath… But perhaps it’s related… And I have checked every symptom of a head gasket issue and I have no excessive smoke from tail pipe. No residue on radiator cap and again no coolant loss… And heat inside car blows fine. I’m baffled.

There is a vacuum device to assist in refilling the cooling system but it isn’t required. Remove the cooling system cap when the engine is cold and check if the the cooling system is full.

The cooling system temperature can be monitored with a scan tool to verify operating temperature. If there is a thermostat failure you will eventually get a fault and check engine light.

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An Avenger isn’t a sports car? … lol … That name makes it sound like a sports car. OP, if you’ll post the model year and engine I’ll see if I can look up the bleeding procedure. Or you might be able to Google it, or find it on one of the chain parts stores websites. The Auto-zone website tends to have this type of useful info I’ve discovered. Try searching for a radiator or water pump for that car on the auto-zone website, and see if there’s a reference to the bleeding procedure. If all else fails what tends to work for difficult to bleed configurations is to drive the front wheels up on ramps and bleed it in that configuration, with the radiator cap off allowing air to escape as the engine warms up. Make sure the heater is set to make.

I doubt the thermostats are the problem, but I have found bad ones before right out of the box, new. For that reason I always test replacement thermostats in a pot of water on the stove first, verifying they open at the correct temperature.

If you have even a very small coolant leak, your reservoir will stay full but the coolant level in the radiator will drop because no vacuum will form in the cooling system to draw the fluid from the reservoir back into the radiator.

I’ve got the same engine in my Jeep. There was nothing special to do to bleed the cooling system after I changed the thermostats a couple of years ago.