MQ Heater Core

[topgeargirl]

Hi, apologies as we haven't been posted on the forum since joining and as hubby doesn't like computers, I do all the posting and we have had no problems... But alas, we now do have one so I am back! Hubby has a Japanese imported 1985 Diesel MQ and the heater core has pooped itself.... He knows he has to take the dash out but we are having a problem locating a manual and a second hand heater core. Does anyone know where we could find one? I've looked online but can't find a thing. Thanks in advance!

[Yendor]

The MQ workshop manual can be downloaded from this forum

http://www.nissanpatrol.com.au/forums/showthread.php?799-MQ-Service-Manual

The manual is pretty basic here's the info regarding the heater core.

You could try a radiator repair shop, they might be able to supply a replacement core.

[kenny2551]

It is probably the heater tap thats rusted out.It happened to mine and I think I got an after market tap from repco or auto barn.I had to put a spring over the hose to stop kinking and feed the hose through the firewall.unfortunately,you still have to pull the dash ,glove box and all the top of the dash out to get the heater out.I do have an extra heater core here but I think you'll find it is the tap.

[grahamap]

My hoses and such are rusted out and non existant! I want to install new ones but I have not a clue as to what I might need and what to connect them to on the engine side.. what did you use?

[kenny2551]

My hoses and such are rusted out and non existant! I want to install new ones but I have not a clue as to what I might need and what to connect them to on the engine side.. what did you use?

When I was getting my old mq ready for roadworthy,I noticed that where the heater hoses come out of the block (and returned to it)there were no hoses.A previous owner found out the heater was leaking(turned out to be the tap)and put a u shaped hose on the block (probably 100-150 mil long )and then taken the hoses off the heater where it connects at the firewall.simply go to repco/autobarn and ask for a couple of metres of heater hose.I'm pretty sure its a standard size but measure it or take a sample with you.once it's connected and you start it up and turn the heater on check on the passenger side interior and make sure it's not pissing out water.If it is the heaterbox has to come out and the tap and core checked.Invariably its the tap that rusts out(steel) not the heater core(copper/brass)A quick roadside fix is to take one hose off the heater and return it to the block when a heater starts leaking and then get home ,take the other hose off and not worry about a heater.personally,even in Qld I like to have a heater.

[grahamap]

I see.. ive got two holes in my firewall that I assume are for water into the core and water out. Connect em both to the block?

[kenny2551]

yes.from memory,you should have 2 pipes sticking out of the firewall.(it's been 2-3 years since i've done mine)If you havent someone might have already changed the tap over to an after market tap.dont mistake the 2 holes behind the air pre cleaner for the heater hoses.the 2 holes behind the air cleaner are for the air con.the heater hoses inlet and outlet are between the air cleaner and the motor.(i'm assuming you have an MQ)anyway,see how you go.

[grahamap]

A/c hoses would be closest to the wheel well, i believe.. all the hoses to the heater have rusted away even the connections on the back of the core! Anyway thanks for the info, ill try find a way to reconnect the core with some sort of adapter or fitting

[grahamap]

Got into the core again to see what size fittings I would need and sure enough the tap was rusted to shit. A bit of heat and wd40 and I had it functioning again however it no longer seals 100%. With it being a rather important part of the engine I decided its best to replace however in the mean time im just going to connect it all up without a tap. Core doesnt leak or appear to be blocked. If I dont want the heater I can shut off the blower and all should be well. I could be wrong and the tap may allow for extra cooling of the coolant (while blower is on and tap is closed) but I dont think it matters too much.