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Okay winter is back better and colder than ever . my heater was really good and strong. Now I have done a de swap and gone through some headaches.... Blah blah blah... Any ways, the heater barely puts out luke warm air. Do you think it can maybe be a thermostat or just a cloged heater core. Or somthin else...?

where does the temp guage sit?

Some peopel block off the holes in the bumper with cardboard to prevent cooling. I'll be doing it soon.

Use a block heater in the mornings, it really lowers the warm up time.

My buddy has a DE probe and it heats VERY well (he drives in an oven) so who knows what your problem is... could be heater core, air bubble in cooling system, waterpump, theromstat, clogged rad even.

Check your coolant level. The most common issue with no heat is that here is not enough coolant in the system. You will need to burp the coolant until no more bubbles are coming up (or only very very tiny ones). If still no heat then check your coolant lines to the heater core. You might have installed them backward.

And of course, check the thermostat!

Ryan wrote:Some peopel block off the holes in the bumper with cardboard to prevent cooling. I'll be doing it soon.

Red Green is back!

Ryan wrote:...t?
Some peopel block off the holes in the bumper with cardboard to prevent cooling. I'll be doing it soon.

Just swap out for a higher temp thermostat. If the thermostat is working correctly, there is no need to block the radiator. It won't get coolant flow until the thermostat opens.

Jim

the car used to heat very well. and randomly it got really bad. i used to drive for like 5 mins in -20deg C weather and id have to turn it off it was so hot... now its total crap. i toped off the coolant and have burped it numerous times... i think it may be the thermostat.

yeah if the coolant is topped up I would look at that as a suspect, just an added note I ran into this situation while helping a fellow mx3 owner, his heater core got blocked up with rad stop leak he had used once to get him out of a jam. if you are draining the coolant I woudl blow out the heater core to make sure that there is no crap stuck in there.

hi yontze.... ha ha
anyway a little more to add to your story....
It seems like there is no pressure in the rad hoses (well the one on the left side anyway)
It can't be the water pump cuz he got a brand new one installed with the swap. So the only other thing that is in the way is the thermostat right????

If the thermostat is stuck open the temparature gauge will indicate low coolant temparature all the time as the engine will not be able to get up to temp in cold weather. If the gauge is showing correct operating temp, warm it up and then turn the engine off and go under the hood and listen to it as it cools down. After about 3 minutes you should hear the thermostat closing. If you don't then it is stuck open. If you do hear it close then it is air in the system causing your heat problem.

I have found that the best way to fill the system is...with the engine cold and off, fill at the engine filler neck. The top rad hose is at that neck so as you fill the block it will also flow into the rad. Fill until it won't accept any more coolant. Leave the cap off and start engine. Coolant will not circulate in the rad as the thermostat is closed, but any air in the block will rise to the top. This should only take a minute and the engine should not have reached a significant temperature yet. Replace the cap and check that the overflow reservoir is filled to the cold full line. That's the lower line. Bring the engine up to operating temperature now and any air in the rad will be expelled into the overflow tank when the thermostat opens and the rad starts to circulate. As the coolant begins to expand it will be pushed out to the overflow tank. Once the engine is up to temperature check that the overflow tank is up to the full hot line. If it is not, air will be sucked into the system when the coolant cools and contracts.

If you do this you'll find that you will have heat...I garantee it. If you find that after a while you get air in the system again, then there must be a leak somwhere. I had found that when my overflow tank (which is not in the stock location) was full it was sort of tipping over and spilling some of the coolant and then as the engine cooled it did not have enough coolant to fill the system as it cooled and air was getting in that way. You could have a bad cap on the engine filler neck that is allowing air into the system as well. It is the highest point in the system so air would be sucked in as the coolant contracts.

you all mock my cardboard idea...

Why do truckers do it? why does everyone else do it?

Because it works. Maybe its not so cold where you all live, but we get into the -40's BEFORE wind chill (not that that matters for cars) and any way you can keep things running at normal temperature is a good thing.

My mother's car tossed her waterpump belt las winter, and she drove half an hour to the city to get it repaired, and it didn't overheat at all. (Yes I know guage is inaccurate without coolant flow, but that long without a belt would kill a motor under normal conditions, and it runs normally)

Ryan wrote:you all mock my cardboard idea...

Why do truckers do it? why does everyone else do it?

Because it works. ....

In a properly functioning cooling system, the radiator is doing no cooling at all, until the coolant reaches operating temperature. Cardboard might reduce air cooling on the engine block itself, but that would be a small factor in a car with low wind resistance like the MX-3

Why do truckers do it? Maybe direct air cooling is more of a factor in a flat fronted cab.

Why does everybody else do it? They don't.

Truckers run diesel engines, way different than gas engine
It takes ~20min for my truck to warm up on a cold morning (to operating temperature)
For my mx-3 it takes 5-10 before its in normal running temperature. Diesels do need to reach full operating temperature to burn diesel fuel more efficiently. Most diesel trucks already come with block heater installed from factory. You don't want diesel to start gelling up or you're screwed.

You're all not listening. The rate at which something cools is exponentially proportional to the differnce in ambient temperature. If its 90º as the coolant leaves the thermostat, and moves through a rad that is seeing a temperature difference of 130 degrees, the coolant cools MUCH quicker than usual than if the difference is only say, 60 degrees. Because the coolant starts at -40 degrees, its likely that if the thermostat opens after 5 minutes because the stuff in the motor is hot, by the time the coolant in the rad makes its way through the engine and past the thermostat, the coolant is not at operating temperature.

This is still onyl valid if the engine manages to maintain a constant 90º on the output of coolant, which I sometimes doubt it does.

It also should be mentioned that when its -40 out, people usually have the heat on full blast, making the heater core another rad.

Reducing the airflow past the rad changes the ambient temp around the rad, and the coolant is not cooled as much, allowing the motor to run at the proper operating temperature.

Do you realize how cold it is here? As the coolant initially flows through the motor, it literally has to increase 130º Celcius. Thats 4/3 from ice cube to boil


And I'm not going to bother debating who blocks their grilles. You clearly don't know what you're talking about, because you can BUY, from the dealership, plates that clip on over factory grilles.


Furthermore, people who live with real winters notice a mileage decrease in colder temperatures, becaues of the fact that the coolant temp sensor is tied into the air fuel mixture (car runs rich when cold) You all know this sensor is on the 'hot' side of the engine. Another proof to my point.

PATDIESEL wrote:If still no heat then check your coolant lines to the heater core. You might have installed them backward.

This makes no sense. Why does it matter which direction the coolant flows through the heater core? A to B, or B to A. Plus, the hoses are moulded, I'm sure you know, kinda hard to mess that up...

Ryan

the blend door for the heater is probly stuck on cold, cause im just guessing you switched it over so you dont have hot air blowing in, in the summer. and you may have some calcium build up in the heater core itself and may need to be flushed out