Hey guys. Was out in the swb yesterday for the first time in a while & the heater wouldn't blow hot air. One of the heater matrix pipes at the rear is hot one is cool so hot water must be getting into the car, any suggestions what this could be?

Has your mechanic struck yet again, buddy...?!

Low fluid level?

 

If it isn't something in the engine bay and it's something wrong with the air conditioning and heater control system... I've hardly worked on it, but I bet it's NASA grade complicated :# :clover:

Don't do the obvious thing and panic about a blown headgasket etc. First thing I'd check is for leaks in and around the matrix - a soaking floor will give this away. When you turn the car off do you hear bubbles going through it? Second- how long were you driving it for? Mines takes until operating temp to blow hot air, it also has a nismo thermostat and a large alloy rad so takes forever to heat up, especially in winter.

Check under your car for coolant leaks, it looks like there's a million places a vg30 could leak from :D

Can't see any coolant leaks, carpet inside is dry & no bubble sounds. The old heater matrix was swapped out a few months ago for a working one. I was driving for over half an hour so plenty of time to warm up.

If only one of the matrix pipes is getting hot then your matrix may be full of sediment and you won't be getting any coolant flow through it.

 

But I see you've replaced it, so it could be an airlock.

When you replaced the heater matrix did you set the heater controls to the highest heat setting to flush out any trapped air in the matrix?

 

There may be a problem with the heater core valve:

 

https://aus300zx.com/xenforo/index.php?threads/assitance-needed-with-heater-core-valve.312258/

Lee Dent changed it, I'd ask him what he did but he's done a disappearing act.

Lee Dent changed it, I'd ask him what he did but he's done a disappearing act.

 

Never trust that a previous owner has done anything, or the work they've done. Run water through a hose through your matrix from the pipes in the bay to ensure its free of mucky shite, then bleed your coolant system.

He wasn't the previous owner he's the mechanic who got the car back on the road. Engine was taken out & flushed only a few months ago so I can't see it being a blockage but won't rule it out.

Most common problem with cold heater is simple air lock caused by the water level been too low, wait till the car is cool and take the rad cap off, and check the water level.

 

Adding water with engine running and whilst the heater is set to hot is the best way to clear any air locks.

 

If the matrix was changed or anywork done in that area it possible the water valve is incorrectly connected, or not if you get what I mean, or given the personal involved maybe its missing ????????????

 

 

Jeff

Thanks Jeff. Will hopefully get time to check it over tomorrow. I'm just not confident with this car at the moment, like you said I wouldn't be surprised if there's stuff missing. She is running well though.

Thanks Jeff. Will hopefully get time to check it over tomorrow. I'm just not confident with this car at the moment, like you said I wouldn't be surprised if there's stuff missing. She is running well though.

 

All joking apart, the valve is cable operated and just like a brake cable in a bike the outer case needs holding in place so the inside cable operates correctly, seen the clip for this missing or wrongly fitted a few times after an inexperienced matrix swap, trouble is its hard to see without removing the heater ecu, the ecu bracket and the cover for the valve. I would of thought though it was tested as working after the swap??

 

Got some pics somewhere or can guide you through by email stage by stage is required.

 

 

Jeff

All joking apart, the valve is cable operated and just like a brake cable in a bike the outer case needs holding in place so the inside cable operates correctly, seen the clip for this missing or wrongly fitted a few times after an inexperienced matrix swap, trouble is its hard to see without removing the heater ecu, the ecu bracket and the cover for the valve. I would of thought though it was tested as working after the swap??

 

Got some pics somewhere or can guide you through by email stage by stage is required.

 

 

Jeff

 

A guide would be great. I'll double check the coolant level tomorrow first to rule out the obvious.

Your thermostat could be stuck Tom, i'd be looking there ;).

Your thermostat could be stuck Tom, i'd be looking there ;).

 

But with one of the matrix pipes being hot the thermostat must be working? The coolant level is OK.

I'm starting to look into this properly now. I've removed all the dash panels so I can get a good look. Does anyone have any pictures of the front with the dash removed so I can see if theres any bits I'm missing. I'm going to change the heater ECU first for a known working one & go from there.

I think this issue is now fixed, need a cooler day to fully test it as its so hot in the zed already but if it is fixed then the problem was another Lee Dent bodge, I'm working my way though them on this zed.

I think this issue is now fixed, need a cooler day to fully test it as its so hot in the zed already but if it is fixed then the problem was another Lee Dent bodge, I'm working my way though them on this zed.

 

What was it Tom ?

What was it Tom ?

 

I'm thinking it was as simple as low fluid level. The rad was removed for the respray so coolant topped up when it was replaced, it's the only thing I can think of for it to suddenly start working. Keith told me there was no anti freeze either so I'm pretty sure it was another basic job that's been bodged by our favourite "mechanic"

No Anti Freeze again,I remember the coolant in the lwb it was horrific !

No Anti Freeze again,I remember the coolant in the lwb it was horrific !

 

I doubt he had ever changed the coolant in the lwb even though I'd asked him to.