aussie983

iTrader: (16)

I bought my 93 max during spring and i guess i never had to test the heater. Well it turns out that the heater, not matter how long i let it run for, will only blow out air thats slight warmer than the ambient air. I dont know if it was like that when i got it, or what happened.

Anyone have any suggestions as to how i can fix it?

Wiking

There may be lots reasons, starting from low coolant, bad flow, flaps open... U have to do some checking.

I'd start from easiest: THE vac hose [15.] intake end, possibly brittled and vacuum missing. On VE, location differs, functionally identical. See details at: http://www.cardomain.com/ride/748507/7

DennisMik

iTrader: (2)

if you have the single overhead cam engine, the vg30, those engines have a high point that trap air and that high point is where the heater gets its water from. nissan had a service bulletin about jacking up the front of the car until the rear bumper touched the ground and then you opened the radiator cap and ran the engine to get the air out. in later engine production, they added a bleeder screw on the top of the engine by the one heater core hose connection. i don't know if your engine has this screw (bolt actually).

look at your engine where a heater hose connects at the top back edge just off center. if there is a bolt head right there on the top, you have the easy version. if not, you can either do it the safe, nissan way or invent some other way.

there might be something in the stickies about this, but i've never checked. it has been discussed a lot.

Wiking

As u never read facts, your story doesnt have any. Next time, read before writin.

DennisMik

iTrader: (2)

which facts are you referring to?

Greeny

iTrader: (43)

You need to check a few things...

1.Look at the temp. needle after driving for a while, if it is not right at the midpoint then you need to replace the thermostat...If it is ok then try #2

2.You may need to bleed air pockets out of the cooling system...

Open the air releif plug then start it up and warm it up to operating temp. this will get the air out of the system...

3. If your still experiencing heating trouble after checking all that,then i would look into the cold/warm doors in the dash for problems....

aussie983

iTrader: (16)

I have the VE if that helps any...

confused1096

Dumb question, maybe. Is the air being blown out at normal strength? If not check the blower motor.

Wiking

Those facts u say u "..but i've never checked....." The ONE fact i selected from your text - which is plain wrong.

Make a deviation this time: read the the given link first. Watch the given pics first. The link shows explicitly all maxima coolant circulation; u cannot get that flow pic serie anywhere else in the world. Its with pics.

Also pls read before write: check the picture above your text, pasted on my msg, and see how short your statement is on facts: "...high point is where the heater gets its water ....." No way it is so.

Note: High point is for air bleed.

Wiking

Following links, youll find that engine specific bleed info also. Flow to core [my pasted pic] is the same for cabin heat, VG&VE.

See for the CDomain Favorite Links...

Greeny

iTrader: (43)

Ooops..Sorry my first pic is for the vg coolant screw....This air relief screw pic is for the ve engine....

DennisMik

iTrader: (2)

wiking -

you're correct in that i was in error about where the heater hose connected. that is the only inaccuracy. in post #4 of this thread where you blasted me, you took my reply to aussie, cut and pasted pieces together to make what looks like a statement i made. i did not type that - you fabricated it - and i don't appreciate what you did.

in general, you came down pretty hard on me. some was deserved, most of it not.
your method of political assination is not appreciated at all.

Wiking

Your own txt, letter to letter. Everyone may verify that. Sits up tHere. No change, just cutoff. I only left the error -issue. For clarification.

My picture/link = fact is still sittin there above u txt, and u dont care to look at it ??? and then say u will not take a look... Once In Lifetime Go to the LINK and try to figure how many hours has been spent to get THE FACTS ILLUSTRATED RIGHT, no wishy washy imagination w/o any checkup.

Guess how many hours?

Error correction is not assasination. The Error itself was minor and not worth mentioning. So if it fits you, lets go forward and forget the whole issue.

aussie983

iTrader: (16)

Yes my blower works fine. The fan blows pretty strong at full speed. AC also blows cold.

I will try the bleeder screw thing when i get home next week and see what happens.

Could someone explain how the coolant affects the performance of the heater? Should i do a flush while im at it. If so does anyone have a howto or a link on how its done?

Wiking

All your cabin heating depends on coolant flow. That is why I suggested first checking how the main adj valve works. Did u do it? No answer...

I dont know if u dont read either, but the valve works & coolant flow is described very detailly in the given link. The cabin heater & hosing is exactly the same on VE&VG engines.

Any main valve checkup starts from inspecting its vacuum hosing. Next, is the electronics ctrl signal available. If they work, both core coolant hoses will be hot when engine is hot (tstat workin), outcoming hose less so.

If that doesnt happen, do the mentioned air bleed. If no hlp, take outcoming hose off to see if any coolant actually flows out. Flush no big deal, just wet. While there, take both hoses out and flush both ways using garden hose tap water. Water should flow freely both ways. Keep coolant glycol from splashing on engine, electronics.

DennisMik

iTrader: (2)

i'm sure you have spent many hours developing your web site and no doubt have a right to be proud of it. i did not say anything about you web site, i did not mention your web site. i was referring to the stickies.

and how is your response of "As u never read facts, your story doesnt have any. Next time, read before writin." correcting my error? i had to ask you what you disagreed with.

i'm human which involves making mistakes and i apologise for not being perfect. and i don't object to someone letting me know that i made a mistake.
but all of your responses to me have been hostile. i don't know why you should be so angry with me.

Wiking

My apologies.

My stupidity - I have read smtg which wasnt there. Yes I should be more polite, I'll try harder. Hope we can get over.

DennisMik

iTrader: (2)

Thank you. that's all one person can ask of another.

as far as i am concerned, this matter is closed and forgotten.

ghostmax

iTrader: (4)

hey aussie, my problem is in the heater valve at the firewall. i have to disconnect the lower vacuum hose (at the heater valve) and reconnect it before the air will blow hot. if i switch it to cold then back to hot, i have to fiddle with the vacuum hose again. it's worth trying and takes only 10 seconds.

aussie983

iTrader: (16)

Yeah thanks guys for the responses. My 93 max is like 90 miles away. I wont be able to try any of this till friday. Ill let u know what happens

yay0

Thermostat? Could be

mordezmoncou

ok based on you saying your heater doesent work
could be thermostat, heater core, or heater fuse (there is a fuse that if its blown heater wont work) (as far as i recall anyways)
take it to autozone. they can check it. they checked my moms and it was a relay.

Wiking

Smbdy has mixed your hose connection. Re-connect them LIKE IN THE GIVEN PIC/LINK above, note also the one way valve location/flowdirection. "it's worth trying and takes only 10 seconds."


mordezmoncou:
- cannot be any fuse, relay, mom. why? For once in a lifetime READ - his answers above.
- ppl do advice not to go to idiotzone...

michaels'max

I recently changed out my heater core, and one of the problems I had in not getting any heat afterwards was that there was no fluid going through the heater core. There is a valve that is located on your firewall which the upper heater core hose feeds from. This valve needs to be open for fluid to flow through, thus so you can have heat. If the lever on the valve is pushed out all the way, then it is open, and thus you should have fluid flowing through the heater core. If it is not then there is your problem. Another way to test this, is to try and "pinch" the lower hose on the firewall coming from the heater core. This is where the fluid exits the heater core. If the hose gives easily or it feels like there is no fluid flowing through it, then there isn't much or any flow of fluid going through your heater core. My advice, check the valve that was previously mentioned. Wiking had a diagram on his site of the vaccum hoses that connect to this valve, if they are not connected properly, which was my problem, the valve may remain shut. This is just one of the few things that could be causing no heat. As others have said, it could also be due to an air pocket(s). And, as others mentioned, you would need to just bleed the system to correct it. Either by using the bleeding bolt, located on the upper driver side of your engine block, or by jacking your car up and taking your radiator cap off while the engine is running. Of course, take the cap off before the engine is at normal operating temperature. As, taking it off while the engine is hot could result in physical injuries (burns).

You had asked previously how the coolant effects the heater. Well, the Coolant flows from your radiator up and around your engine block to cool it from all of the heat it gives off while it is running. There is a lot of heat given off by all of the "explosions" occuring during operation (combustion of gas and air forcing pistons to go down). If it was not for the coolant, your engine would over heat and well.....very bad things would happen. This heated coolant flows through the heater core, which is a small radiator. The fan then blows outside air through the heater core's fins which then turns the blown air hot, and thus hot air. A very ingenious, yet simple system I think. This is of course also the reason why you don't instantly get hot air when you turn on your vehicle. Your vehicle's engine has to reach normal operating temperatures before it can heat up the coolant enough to allow heat.

Good luck.

aussie983

iTrader: (16)

Okay, looking at it tonight heres what i found:
-Temp gauge is a little bit below mid level when full warm
-All the large hoses that are in the middle of the firewall (both upper and lower) seem to be quite hot to touch...so does this mean hot coolant is at least getting to the core/cabin?

So i cracked open the screw when fully warm and let some coolant drip out. It seemed to help a tiny bit. The air used to be cool and now is slightly warm. It still is nowhere near "HOT". Now i checked out the lever? it looks like its attaced to some electrically controlled actuator? Im not sure which position is "open", but it always seems to be in this position:



It seems i can turn it clockwise when the engine is off and i hear like a whooshing noise like air coming out of a small hole. Is this normal?

Im kinda confused where to look next or what to do? Im pretty mechanically inclined, but i have never really looked at how the cooling/heating system works.

Wiking

You'll stay confuzean if u dont ever read what is written.

The link explainin the system and numbers/functions in the pics, is way up. Will u read? No. Then stay that way...

aussie983

iTrader: (16)

Um my firewall does not look anything like that... i dont have a VG.
And yes i did look. I have a general idea of what the function is, but if you READ MY POST, i asked for specifics relating to that lever, which your picture does not explain. I DID check if it mechanically worked- if you read the post i said it DOES TURN clockwise... but what that means, im trying to find out. Does it mean the lever isnt stuck, but maybe the actuator is not working? I dont know which position the lever is supposed to be in when its working properly.

I was hoping someone could answer that.

You say check resistance and voltage too... But what are the specs? Im not sure which connector to test?
I am reading what you put up, but its not enough for me to go on, that is why i reposted for more details...

Wiking

Picture has parts id'd. Web page has got the story detailed, like: 14d is the valve lever, 14c the vac operated actuator moving the lever. etcetc ...as explained on the web page. "Favorite Links" there does contain some more 'real info', but needs clicking.

When u adjust temp, electronics should operate the vac valve [14] and cause vacuum to actuate [14c] and thus cause valve lever [14d] movement.

Engine is engine, the J30 chassis in 3gen is the same. Firewall is the same, valve location/angle differs due to intake space requirements, so does valve vac hose connection to intake... ball is a ball be it red/blue/small/big/round/flat etcetc...


NEXT phase: How flaps operate inside cabin. If they do not, air does not pass through core, no heated airflow. Again, see the web page, detailed illustrations, lots better than the FSM.

After this, core flush...

aussie983

iTrader: (16)

Okay my question still stands. How do i test the Valve Actuator. It seems like since i do think hot coolant is getting to that region by feeling the piping, that the valve may not be? It seems like the lever is turned 180 degrees on the VE (the actuator arm is on the side closer to the firewall)

Wiking

- As said, actuator moves while cabin heat lever is adjusted, engine idling.

- Direct actuator response tst: take an extra 'working' rubberhose, connect to idling engine manifold (or whatever vac source), other hose end directly to [14c]. Valve lever will open fully.

- To be sure if valve itself fully opens [might be partially broken], it has to be taken in hand, and viewed. Undirect tst is to bypass the valve assy alltogether with steel pipe bit.

If exit hose gets hot, valve, core, engine Tstat & whatever are ok. If hot air is missing, problem is the air -flap in front of core.

Compare hosing; has to be connected like in my pic.

Electronics: The ctrl comes via connector [16] to the electronic ctrolled vac valve [14] . I have not measured the voltages, dive into that via mentioned "Favorite Links"

michaels'max

to answer your question on the valve, although I did answer it in my last post. In Wikings picture noted 14d. you can see that there is a lever that is going inside of a cylindrical device which then has a vaccum hose feeding out the other end, which is connected to that actuator you mentioned. Well, if that lever is pushed out of the cylindrical item (sorry I don't know what it would be called), then the valve is open, if it is pushed in to it, then the valve is closed.

aussie983

iTrader: (16)

what do u mean by pushed out? its kinda hard to see, but it seems like the lever in my pic, is normally in that position (when engine off and even when warm). When i manually move it, it can move clockwise like maybe around 45 degrees? and it will spring back to that position when i let go. however it does not ever move to that position by itself. I dont really see what is getting pushed out?

Wiking: thanks i just testing the vacuum, by bypassing that electronic thing, and directly connecting the valve directly to the intake manifold, and the lever moved right across.

So basically you are saying, once the car is warmed up, the lever (with everything connected the original way), should automatically move the way that it moved when i bypassed it?

If so, then it would seem that its the electronic thing that is faulty? Anyway to fix it?

Wiking

[14c] is a airtight box containing a diaphgram. Inside is a spring pushing the diaphgram left (water valve closes). The flat metal rod is connected to this diaphgram acting like a piston. When vacuum is inserted into this 'box', the diaphgram is sucked to rightmost end, and thus the flat rod moves right opening the valve.

No idle, no vacuum, no movement action.

If it never moves, as said many times over, your hosing is craked, wrongly connected, one way valve blocked and/or u dont get electronic ctrl to the valve [14]

Go and find the info for electronics - as described.

All electronics can be repaired. Easiest way is to find spare modules from junkyard. But start from fuses first.

Kimuel

I am not sure about the 93, but I have the same problem on my daughter's 92 SE, which I bought this summer. According to the FSM, the water valve is powered only when the HOT/COLD lever is in full cold position. There is a microswitch which is activated by the HOT/COLD lever, so you have 12 volts at the solenoid when in full cold position and nothing when off that position. Power (indirectly via vacuum) causes the valve to close. Without power the valve should be open. Lack of electrical power is not the problem. I disconnected the electrical cable to the underhood solenoid that controls vacuum to the water valve and opened the water valve by hand. It stayed there for me. Perhaps this will work for you.

I have not checked the plumbing on the vacuum hoses. That is an excellent idea. I hope to have more time to think about it before spring.

BTW, you can find a TSM in pdf format at www.phatg20.net. It is huge, but very impressive.

aussie983

iTrader: (16)

Okay here is a pic of how its hooked up:



(I moved the tubing around and out of the holders, so you could see the connections better)

Based on what youve said, it looks right. Vacuum coming out of IM is good, but somehow its not getting to the valve. All tubing looks okay. Nothing is cracked...the connections are a little loose, but i dont think enough to be losing vacuum.

Now, funny thing is, i hooked up the vacuum hose directly from the IM to the valve, and yes the lever moved across. So i let it idle for like 2 minutes like that with the heater on. Strange thing, even with the lever across, there was no change in the temperature of the air coming out of the vents.

So this has me puzzled, unless both the electronics is defective and the heater core is not working right?

Wiking

Carefully reread all that has been said before.

At this point, u valve waterflow has not been ensured. Reread how.

To tst valve[14], disconnect its hose [14b]. Vacuum in its OUT -port will be on/off according cabin temp hot/cold adj. If not, disconnect the two connectors, ground one pin, insert +12V to other. Vacuum present?

No: valve[14] is faulty
Yes: valve[14] is Ok, ctrl signal missing.

traitorzxiong

Anyone know why my heater and AC doesn't work anymore? Is there something wrong with my climate control? The cars been sitting for like 3 weeks now and I go start it up and the clmate control doesn't work at any speed? I checked the fuse, wires, and plugs and everything looks good. It was working great before I parked it for 3 weeks. Need help asap.

Thanks

wsilvers

Check your waterpump.The propeller in mine was worn and it could not push coolant through the heater core.

mtcookson

iTrader: (2)

the first and easiest thing to check is the fresh air valve:



If its not closed, you won't get heat. If you still don't get heat after checking that then you need to check the rest of the problems.

Also, above I believe what DennisMik was trying to say is that the early VG Maximas were very prone to getting air into the coolant system due to, I believe, the heater core being too high. Nissan recommended to lift the front end of the car around 30 inches to get the air out of the system when filling the coolant.

blackandwhite

iTrader: (3)

I don't know if this will help YOU, but on MY car I had a similar problem, blower blew at full speed, but no heat. It turned out to be a vacuum line that was disconnect from a little valve that was on the firewall.