heater problems

[Ones&zeros]

hey guy im kinda new and my friend owns a maxima 89' with no heat the fan turns on but it wont let out hot air any suggestions.ps theres a radiator leak. thanx.

[Nahkapohjola]

Do not drive before u replace rad. Add coolant, bleed air out.

While the rad is out, take heater tubes off [from engine] and test flush with garden hose that water runs through.

[Ones&zeros]

Could It Not Be The Heater Core? Because He's Been Driving The Car Like This For A Month Now.

[Nahkapohjola]

Originally Posted by Ones&zeros

Could It Not Be The Heater Core?

If u do the test I said, thats when u will find it out.

Rad leak is not the reason for no heat. Its gonna be the reason for blown gasket. Yu'll ruin your engine by driving, but then its all yours...

[Ones&zeros]

Head Gasket?

[Nahkapohjola]

Engine cooling is a pressurized system. If no pressure, cooling does not operate as designed: cylider heads are hottest and you risk valve burn or gasket leak due to heat bent alu heads.

Rad leak=no pressure


Btw:
Cabin heater valve is (VG30E J30 -93) electronically controlled, vacuum powered valve inside engine compartment:
Its located on engine bay wall, under the hood. It gets it operating pover via vacuum tubes from engine(check if leaking). It is electrically controlled (check its coil resistance and that it gets its control voltage). Open and check that it is mechanically operative.

[Ones&zeros]

Cool Cause His Temp Guage Stays At Normal Temps, And Sometimes The Heater Works But Most Of The Times It Does'nt. Ill Tell Himabout It.

[Nahkapohjola]

Originally Posted by Ones&zeros

Cool Cause His Temp Guage Stays At Normal Temps, And Sometimes The Heater Works But Most Of The Times It Does'nt. Ill Tell Himabout It.

"Temp Guage Stays At Normal
- Why not? Cooling system that is not pressurized as designed allows gasbubbles =airpockets formation. Those points do not adequately cool, especially at the hottest areas, cylinder head. Leaking rad will ruin the engine, question is just timing.

"And Sometimes
- gas bubbles block flow, do not have a timetable...

[James218]

Originally Posted by Nahkapohjola

"Temp Guage Stays At Normal
- Why not? Cooling system that is not pressurized as designed allows gasbubbles =airpockets formation. Those points do not adequately cool, especially at the hottest areas, cylinder head. Leaking rad will ruin the engine, question is just timing.

"And Sometimes
- gas bubbles block flow, do not have a timetable...

My 93 nissan is having the exact same problems as one%zeros friend, I figured the problem couldn't have been many things, the thermostat, heater core, or water pump. Checked the thermostat it was fine, the water pump was fine, but what a bitch to take off and replace. Now i'm stuck with no heat in 10 below zero weather. Any suggestions for me?

[Nahkapohjola]

Remote diag is not easy...

Figure out how your tubing is routed. Start cold engine and track how the water temp that raises gradually, seep through your tubes. (Check the mentioned valve.) If they all get hot, the air ctrl flaps might not work and blower blows always the air past the heater. Ctrl rod/wire loose, broken mech?

Heater core is almost impossible to become totally blocked, leak is known to happen in maxima. (Btw. that burns the ECU)

Tubing might collapse and form block. More propable is gas bubbles which tend to form total blocks in water circ systems. This phenomena also blows your engine head if rad is elaking. There is a bleed valve; open it slightly so that its bleeding a little, drive one hour (keep water level up). This will get all 100% air out.

Hmm...
- it is a gas bubble if cooling helps
- somehow broken rubbertubing (inner ring of the tube ripped off, blocking flow intermittently)
- Factory Installation time debris has now formed a block
- some other external force pressing/bending it closed

[maximagirl420]

A bad heater core always floods the floorboards, even when you are not using the heater. But before it gets totally shot, it stops putting out heat adequately. If the radiator is leaking, change/fix it. But when you fill the radiatior, there is an easy way to make sure you don't get any air bubbles. Just buy a radiator fill kit that comes with the bowl and a rad. cap with a hole in the center for the bowl to set in. It's like $12. It's purpose is to keep the fluid above the highest spot of the engine, working air bubbles out itself until it's full. But air bubbles in the system cause hot spots in the engine, and you would notice the car heating up faster, and a few degrees higher. And I don't reccomend using NAPA heater hoses.

[James218]

I probably have to replace the hoses, I'm sure it wouldn't hurt. Although the hoses seem to be just fine from the outside. The heater only working speratically, it must be some particle blocking the flow now and then. Im going to have to check for a bleeder valve, Im not formilar with this bleeder valve, so if someone could help with the location that would be awesome. (There is no leaking I've already checked.) I'm now thinking it could be an air bubble, which is making it overheat, and the cabin heater valve thats causing the heater to blow cold air. I'll be able to work on it soon, then i will get back to you all.

[James218]

I found a cracked vaccum hose. As soon as I get some spare time to pick up the part, I'll replace it and fill you all in.

[Nahkapohjola]

Originally Posted by James218

I probably have to replace the hoses, I'm sure it wouldn't hurt. Although the hoses seem to be just fine from the outside. The heater only working speratically, it must be some particle blocking the flow now and then. Im going to have to check for a bleeder valve, Im not formilar with this bleeder valve, so if someone could help with the location that would be awesome. ...

"to replace the hoses
- just check flow, condition

"heater only working speratically
- air bubbles

"bleeder valve, ... the location
- Follow the hoses, near intake. If u do not find, juts loosen the hose clamp to produce a tiny leak.

"I found a cracked vaccum hose.
- if its in the end, just cut that part off. Vulcanizing rubber 'tape' makes a temporary repair.

[James218]

Ok I repaired the vaccum hose, that didn't work. So I completely took out the doe valve (cabin valve) and put in a plane old manual valve, from a water heater, heat still doesn't work. The heat will put out if your cruisen down the road in 2nd gear reving the engine to 4 grand, the heater will blow really hot air, but as the rpms drop so does the heat ( heat doesn't drop right away but eventually.)
My next step is to work the bubbles out (if any) if that doesn't I'll take it to some place and get it flushed, I've heard of getting it mechanically flushed or something, I don't know but we'll see. I'll also replace the hoses, I'm sure that couldn't hurt.