bigred177

I have done some searching and I think I have the heat issue narrowed down. I just want to double check with people here with a little background on the car.

The car has 150,000 miles on it. We got it with 32k. The coolant has not been changed since we've owned it. I just checked and it looks pretty cruddy, but it is at the proper level.

The heater does not blow hot. I can turn the HVAC system off for awhile and turn it back on and it will blow hot for about 15 seconds. This makes me think that the front heater core is plugged up. The back air acts the same way, so I think that heater core is plugged up too. Is it likely that they are both plugged up given the condition of the coolant? The temp. gauge comes up to about halfway, so I think the thermostat is still good. I feel like I'm due for a cooling system flush and try to unclog the heater cores. What is the best way to go about this? Should I change the t-stat at the same time?

Next, it is throwing a P0430 code. Again, the car has 150k miles and has not had the O2 sensors changed. It still averages 15.8mpg. Is it likely that I just need to replace all 4 O2 sensors and that will solve the problem? About 15k miles ago a few of the coil packs went out and we only changed the bad ones and their plugs. The car does not feel like it is running rough at all. Every now and then if you are accelerating from a stop the engine will hesitate, but that doesn't happen very often. There is a big rattle from the driver's side of the car sometimes when the car is in gear and at idle. I haven't had a chance to get under there and figure out what that is yet.

Also, the car ran regular unleaded gas for about 30k miles. If that affects anything.

Sorry to ramble, I'm just trying to think of anything that would help in the diagnosis.

Thanks

Bert

The more information, the better. You're not rambling.

The heater cores could be plugged but one check is to run it until it's hot and turn the heater on. Then fel both heater hoses for each heater core to see how hot the hoses feel. If they're both hot, it could vary well be the blend door motor.

It might help to clean the MAF with MAF cleaner. The O2 sensors usually keep on working. I wouldn't just change them out. Check the rattle underneath. It could be the Cat falling apart inside.

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Bert

bigred177

From what I've read, even if the heater cores are plugged they can flow enough to heat the hoses up; just not enough flow to heat the air. Is this this right? What are the odds that both the front and back blend doors broke around the same period of time? I'll go give them a feel, just checking.

And I'll do that on the MAF. That would sure beat $60x4 plus changing them. We'll see if it helps.

Thanks

bigred177

One bump to see if anyone else has any thoughts before I tear into this thing.

Bert

Have you done the above?

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Bert

bigred177

I am not in the same town as the car right now but I'm headed down there soon. I just wanted to get a list of things to do so I could spend as much time working on it as possible.

I still really feel like it would be unlikely both blend doors would stop working right around the same time. I guess we'll find out soon.

I'm not sure which is worse: fixing the blend doors or trying to get the heater core hoses off to flush them.

Bert

I would feel the same way about the blend doors. Ver unusual for them both to go bad at the same time. It may be in the control for them. Unless stop leak has been added, the heater cores don't generally plug up.

__________________
Bert

bigred177

Well I finally got down to work on the car today. I ran it until it came up to temp. and then kicked the heat on. I ran the heat for a bit on low and it stayed hot. When I kicked the fan up to high I could feel the air cooling down. I put the fan back on low again and the air started warming up again. I went out and felt what I am pretty sure are the heater core hoses and there was a significant difference in the temps. between the two. I killed the heat and the outlet hose warmed up a bit.

I really feel like is is a heater core issue rather than a blend door issue now. After reading the other recent thread about the 01 Expy, I'm a little nervous messing with it won't help now. The coolant was last changed about 2 years ago when a new radiator was put in. The overflow bottle has some crud in it because it had been awhile before that.

Maybe I can hook a water hose up to the return hose coming from the core and blow some of that stuff out backwards? Either way it seems like I am due for a flush.

The rattle from the cat. (?) only happens every now and then; I can't make it happen when I'm actually working on the car. Is there any good way to very this is what's causing me CEL? Or just any good way to make it rattle? (ha).

On a different note, a mech. crawled under the car the other day and said that the ream main seal is leaking. I looked and that does appear to be the case. He said that you HAVE to take your car to the dealer to have it fixed because normal shops can't separate the engine and transmission? I have some pics to see if it does indeed look like the RMS is leaking.

Pics later, can't seem to get em to work right now.

Thanks

bigred177

I am going to do the radiator flush tomorrow. Since I feel like the core(s) are clogged I was going to hook the water hose up to the return line and see what I could blow out backwards. I have heard that these heater cores are fragile and I'm a little nervous about putting too much pressure on them. What is a good gauge to see if I'm getting enough pressure to unstop anything in the core but not enough to break anything?

I figured after that I would pull the therm. out and flush the system with water a few times then fill with chem flush and then use one of those t fittings to completely flush with water and then add coolant and a new therm. (just want to make suure the procedure hasn't changed)

Here are some pics of the tranny area with the oil on it; just for fun so yall can see how much is leaking.

bigred177

What temp. therm. do y'all normally put back on there? It looks like there are a few options.