Hello and welcome to Just Answer.

My name is XXXXX XXXXX X will try to assist you with the no heat issue.

If the engine is coming up to temperature and noting that your car is a 1998, there is a good possibility that the heater core is restricted.

Check the two hoses that lead into the core at the firewall. Both should be almost too hot to hold and of equal temperature.
If one is is colder than the other then the core is restricted and you will have no heat.

Flushing the system will often not solve this.
In order to clean out the core it will need attention on it's own.
Undo the hoses and put on a couple of hoses on the end of the core pipes. Pour in some solution to remove lime buildup such as CLR.
Let it sit for a few minutes and flush it out well.
The use of compressed air would also be a good idea to blow it out.

Your questions or comments are welcome.
Thank you.
Bernie.

OK, you did not mention that previously.

When you move the control from hot to cold can you hear anything moving or a change in air flow pitch?

Have you already checked the heater core?

Hello.

Could you please answer my question to you on the movement of the heat door?
This way we can determine the cause of the problem.

There are many components that also control the door movement.
If we can determine if it is or isn't moving we can get to the root of the problem.

Thank you.
Bernie.

Hello.

No, a plugged up core will not cause an overheat in most cases.

Check out the heat door for movement and the heater core hoses and get back to me.
I will be on for several hours yet today so no rush on my part.

Thank you.
Bernie.

OK, good!

Hello.

This dialogue will remain open for us to communicate.
I will be on for most of the day tomorrow.
You can reply to me anytime here.

thank you.
Bernie.

So it does move.

Have you checked the heater core supply lines?

OK Keith.

See you tomorrow.

Bernie

Good morning Kieth.

Follow the process I described before on flushing it out.

I use a couple of pieces of heater hose long enough to slide over the heater tubes.
Then I pour in Muriatic acid in one of the hoses and let it sit for a few minutes. Then I flush it clear with water and blow it out with compressed air.

Muriatic acid is very strong and safe use is very important. Safety goggles and protective clothing is essential.
CLR is much less potent and will usually work. It may take a couple applications.

Questions or comments on this subject are welcome.
Thank you.
Bernie

Remove what you need to access it Keith.
I think it is the air cleaner ductwork and the top cover.

Hello Keith.

Was there much stuff come out with it?

Did it improve the heat?
If it did, it may need to be done again.

Bernie

Are the two hoses equally hot now with the heater on high fan?

Well it must have improved. One was previously colder.
Have you taken the car for a drive yet to test it?

Give it one more try Keith.
How much did it improve?

Hello Keith.
Here is a service bulletin that may relate to your issue.

NUMBER: 07-002-02

GROUP: Cooling

DATE: Feb. 4, 2002

A vehicle may exhibit **low or no cabin heat,** engine overheating and/or coolant bottle damage after service has been performed on the engine cooling system This may be caused by lack of complete ** filling or** refilling of the system with coolant/antifreeze.

DIAGNOSIS:

When refilling the engine cooling system after any service operation which required a complete or partial draining of the engine coolant, the following Repair Procedure must be used to ensure a complete fill of the engine cooling system. This is a Repair Procedure clarification.

EQUIPMENT REQUIRED:

REPAIR PROCEDURE:

OK, let me know.