The heat in my max only works when I am excellerating , once I take my foot off the gas pedal the air begins to get cold. Theres no problem with the car warming up at all.. anyone think it could be the Thermostat?

problem 2.. On a cold start if I put the car in drive without letting it warm up the car stalls and engine shut off. When I restart it , it cranks and shuts off unless I give it gas then it will run fine until it warms up then Im able to drive the car normally. In 11 years that I have owned the car it has never done this. Any ideas on what the problem could be ?

 

my friend has that problem in his jetta. i think the heat problem has something to do with coolant not getting to the heater core

http://www.trustmymechanic.com/newsletter4.html

that's an article explaining what it does and how a faulty core can mess with your heater.. but not the best website

 

pretty good information in this link.. but it still doesnt help me pin point what the problem maybe. I guess replacing the termostat is the easiest and cheapest solution. It doesnt seem to hard to change looking at the instructions how to do it.

 

ya plus they're cheap.

but check for leaks before you do it. easiest way to check for a slow leak is to look at the coolant. if its a little brown then you probably do. get it warmed up and run it hard for a couple minutes then inspect your engine for any leaks. hoses are really easy to replace and you dont want to fix the thermostat if it aint broke!

 

Try it at a stop, rev up the engine and see if you start getting heat. Sounds like you just need to bleed it, happen to work with the cooling system recently?

When's the last time you cleaned the TB and IACV?

 

For a basic check of coolant level, color and leaks. Then water pump, thermostats, and heater core. Thermo is a easy fix, but best to pin point the problem before just replacing parts. As well as plugs with throttle cleaning and iavc for sloppy starts.

 

I definitely need some maintenace. I haven't cleaned the Tb and IAVC in God knows how long. Could that be causing my stall problems on cold start? But as far as the heat not working... when I rev the engine I get heat once engine temp is normal ..foot of the pedal cold air. I don't think its the termostat because I read in a link posted here if the t stat is bad the car will have problems warming up and I have none.

Maybe I just need a coolant system flush as well as Tb and Ivac cleaned...not sure. I have to check the coolant level and peek around the hoses and see if theres anything is unusal.

 

If your car is running and stays in the "normal" zone when warmed up, it isn't the t-stat.

Some possibilities:

Water pump impellor failing or pump belt loose causing water to not circulate properly (you'd probably see the temp guage moving around if this was the case though...)

Fan speed changing (alternator? see belt question above. Maybe bad resistor in auto fan circuit?)

Heater core issues. Corollary: water not getting to core because of air in the system or water pump not working.

T-stat stuck open would mean cold all the time, not hot-n-cold. t-stat stuck closed would mean overheating. Easy way to check is let car warm up and feel top rad hose. It s/b hot.

IMHO, some piece of the story is still missing. What else can you tell us?

 

Honestly theres nothing else I can tell you. Fan circuit works fine, if there was an issue with the water pump wouldn't I have over heating issues? T sat... hmmm have no over heating issues but maybe can still be the problem. I'll check when I get home I'll let it warm up and feel the top Rad hose and also check the coolant levels before hand and see what I come up with.

What I have described above is exactly what is taking place. Funny because I have no overheating issues of fluctuation of them temp gauge. When the car warms up it runs fine. Just the heat will get hot then cold depending on if my foot is on the gas or not. And also the stall issues on a cold start.

 

In the 11yrs, how many times have you flushed and replaced the coolant?, Sounds like your heater core is clogged up. if it is, it probably needs to be replaced.

 

I havent done it once a year and I am guilty of that . It does need a coolant flush I havent had one in a while. But if it were the heater core why do I get heat when Im giving it gas? Wouldnt the heat just not work at all?

 

You are either low on coolant (that's where my money is), or you have a problem with the coolant temp sensor.

 

If you've done it more than a couple of times in the 11 yrs then you should be fine.
Sometimes a partial clog restricts the amount of water flowing thru it. When the engine
is revving the water pump is forcing the water thru the restriction. When @ idle not enough pressure to force the water thru. Try to find the hoses that go thru the firewall to the heater core, and feel them both if 1 is warm and one is colder then you probably have a restriction there. if this is the case you can try to gently reverse flush the heater core,. warning*** this could cause the core to start leaking, I've only had my 95 se for 9 mos., so don't know where the hoses are to help you try to find the them. Always try the easier solutions first. gool luck

 

I forgot...sometimes its the heater valve not opening up all the way on other cars, don't know about the max's. the heater control feels electronic.

 

Good tips here... but if I were on coolant wouldn't I have problems overheating? I doubt my heater core is leaking I have no signs of coolant loss in the car and levels appear normal.

 

 

No I have not done any work on the car latley. I have agood amount of info to check this out. I'll post back when I find the problem. Any way to diagnose a faulty thermostat ?

 

So I spoke to my mechanic and he said he's going to start with replacing the Thermostat which I dont think is the right thing to do. He tells me If I never changed it before to replace it and its the cheapest place to start. But he quoted me 150 bucks to replace it and Im thinking if thats not the problem then it was changed for nothing. I checked the Haynes manuel and I found NO trouble shooting guides for the Thermostat.

I doubt my problem is the Heater core and so did he because I would be loosing coolant in the passenger side cabin and Im not. I just disagree with part changing but I guess I have to deal with it. I'll report back once its done.

 

1. even without doing work on the car air pockets can form in the cooling system.
2. use a pot of hot-boiling water and a thermometer. if it opens at the correct temp according to spec it's fine

 

Took the car to my mechanic and here's what he came up with.

Hesitation on cold start due to EGR tubes plugged and TB needs to be cleaned. Will also replace engine intake gaskets and clean up the engine. ( had traces of all oil leaks all around the area of the gaskets)
heat problem due to leaking water pump ( said I was low on engine coolant) and will replace tstat while he's at it. parts for t stat and water pump $150 his price not used.

Funny because on my way to his shop I had a CEL light come up. Turned out to be EGR code 0400 , rear 02 sensor 1326 , and knock sensor 3025 ( second time replacing this knock sensor.. is this a common part that repeatley fails? Damn thing is $163 bucks.

Have a lot of front end noise I have been trying to pin point the source for about a year with no luck , he found torn inner axle boot, front stabilizer bushings worn out. Front lower control bent ( probably happened when the car was stolen in 98)

So for all this work he quoted me 1,700 parts and labor. I know the water pump is a lot of work as well as cleaning the EGR and replacing the engine intake gaskets. Do you guys think this price is resonable for all this work and parts?

I know the car needed maintenance so I expected to spend a lot of money to fix it but I didnt think it would be 1700 and that he would find a leaking water pump. Sucks that it happened now around Christmas.

 

FWIW, you never want to quote OBD-II codes without the P in front of them, gets confusing as the A32 ECU also has a seperate set of codes that are just 4 numbers, and indicate different things than OBD-II. For example, knock sensor is P0325 and 0304 in the two different meanings.

Knock sensor is only ~$50 from eBay, OEM part. No need to replace that until you've done the O2 sensor, see if it goes away on it's own.

Clogged EGR should have zero affect on startup, as the EGR isn't even active then. If it was, then that would likely cause some startup issues.

Is he saying that you were low on coolant specifically because of a water pump? Did you not top off the coolant and bleed the system to see if the heat problem went away? Is the water pump actually leaking at all?

 

Sorry about the mis info on the codes there was a P in front of them but I left it out didnt know it made a difference. I asked him about the knock sensor and that it if could be a ghost code.. he said he reset the ECU and it came back. I didn't know they were that cheap on EBAY unfortunatley I already odered it from Courtesy Nissan. Next time I would be so hastly to have it replaced. So once I get a code for rear o2 does that mean it needs to be replaced? How does a faulty one affect the operation of the exhaust?

Yes he said the water pump was leaking and I believe him he works for Nissan as a mechanic for years and know's our cars well. As for bleeding I dont even know how to bleed the system. If I had a garage I would learn how todo these repairs on my own but I park my car outdoors so doing a water pump especially in the winter is tuff. I just like to know exactly whats going on with the car.

What about the TB would that affect start up?

 

Yes, a dirty TB and IACV will cause those sort of issues you're having on cold startup. Have him clean both of those.

Bleeding the system you can really do just by parking with the front end raised off the ground, like drive up onto a curb or something, then just run the car with the heat on high and the rad cap off until it stops belching.

The KS code can get tripped by an emissions related code, such as an O2 sensor. If he reset the ECU (cleared codes, I imagine he meant) and still has all of those codes (after he drove it quite a bit, I hope), doesn't necessarily mean that the KS is bad.

Cancel your order with Courtesy, it's not a huge thing to need replacing anyway. If it still comes up after the O2 sensor is replaced, codes cleared again then just grab it from eBay.

Rear O2 code generally does mean it needs to be replaced, of course it could be a wiring issue, or other things. If you're curious, you could always test it per the FSM. A faulty rear O2 won't do anything but light the CEL, that's all. It only checks the exhaust to see if the converter is functioning properly.

 

Courstey said the parts shipped today so I think its to late to cancel now. As for the rear o2 I would still need to have it replaced Im assuming for the CEL code to go away. Other wise I will fail inspection because the cel. And what does IACV stand for? Intake air control valve im guessing?

 

damn i found a knock sensor on ebay for 28 bucks. Whats the difference between those and the original nissan ones? any experiences with these aftermarket ones? I wonder if they last as long as the originals.

 

Idle Air Control Valve.

Most of the ones on eBay are OEM parts.

 

really.. I wonder why they are so cheap on ebay and through a Nissan dealer they rip you? $165 from courtesy Nissan. Im gona see about returning the knock sensor. Have you purchased the o2 sensors from ebay as well?

 

Just picked up an OEM KS from ebay for $52 same part number and all. So I will be returning the one I ordered from courtesy Nissan for $165 what a rip off. Thanks for the info bro.