Heater not blowing hot

[jwfchase]

I have a question in the thread titled "Heat issues" to do with the heater, as opposed to engine heat http://www.delica.ca/forum/heat-issues- ... tml#p91545

In a nutshell can anyone tell me where to look for the heater core(s) and what I am looking for to identify it as such? (I'm guessing rad hoses...)

[dfnder]

If you are not getting any heat to the heater then that can be serious. Make sure your rad fluid is all topped up pronto but it could be your controls are not opening up to let the hot coolant into the heater core. Whenever I have had this problem it has been low Rad Fluid or a blown head gasket. Have a look through the wiki to see where the heater core is. I hope it isn't serious.

[jwfchase]

coolant levels are good, just had a bunch of work done on the rad and the thermostat replaced. There is a bit of heat, ie when it is cold outside the heater blows air that is not cold (but not warm either.)

[jessef]

the two coolant lines that go up through the firewall. remove them and put on temp hoses . one to a garden hose and the other just out. turn on the water and it will flush out all the crud that has caked up inside the heater core hopefully clearing it all out so that hot coolant flows through there = heat.

[lrp374]

Is it both front and rear heaters or just the rear? Is your temp gauge at the same position as before the new thermostat?

[jwfchase]

Both front and rear.
The engine is running slightly cooler than before the work, but normally sits about 1/4 up on flat ground, and up to about 3/4 up (on the stock coolant temp gauge)on long hills. Even when the temp gauge is up higher than it normally should be, the heater blows tepid air (and it's not even particularly cold out!). From what I've been reading, I suspect the heater core has a lot of crud built up in it.

[FalcoColumbarius]

When was the last time that you reverse flushed your system?

[jessef]

If you plan to do a cooling system flush knowing that the heater core is suspect blocked, you run the risk of that stuff ending up somewhere else in there.
Best thing to do is to pull the hoses off the heater core box and do the garden hose in out and reg hose out to a bucket for the other or have a shop do it. This will eliminate any crud from the heater core plugging up the rest of your cooling system (thermostat/rad).

[thedjjack]

how hot is it getting? how hot is the top rad hose after you run it? Your thermostat maybe stuck open....

I would also flush the heater cores as per Jesse suggestion. IF no difference change the thermostat it could be stuck open (thermostats quality has significantly gone down).

[naterade]

I have a similar problem, the van interior just doesn't get hot enough in the winter. It gets rather uncomfortable on long trips.

I don't want a repeat of last year, so I will try Jesse's suggestion and report back. I'll see if I can do it this afternoon.

Does it matter which direction I flush the water? (ie which hose goes to the garden hose?)

[thedjjack]

I would flush both ways (it will help to get the debris stuck on the fins in from typical single direction flow)..

Catch the first bit with antifreeze in it an recycle. Also, check that you engine is getting warm enough. Blocking some radiator in the winter in Calgary is probably not a bad idea just watch the temp gauge and pull off in chinooks!)

[jessef]

Don't forget to bleed the cooling system after the flush.

L300 - remove the rad cap (while engine is cold) and top it up. turn it on and let it run watching the bubbles come out (air pockets). This process may need to be done more than once to get all the air pockets out.

[thedjjack]

For bleeding I find parking on an incline helps keep the Radiator as the highest point (car ramps ect...)

[jwfchase]

If you plan to do a cooling system flush knowing that the heater core is suspect blocked, you run the risk of that stuff ending up somewhere else in there.
Best thing to do is to pull the hoses off the heater core box and do the garden hose in out and reg hose out to a bucket for the other or have a shop do it. This will eliminate any crud from the heater core plugging up the rest of your cooling system (thermostat/rad).

CVI did a major service in August on the entire cooling system, replaced tstat, etc.

[thedjjack]

Because it was just service I think it is a stuck thermostat...how warm does it get? how hot is the top rad hose? If it is stuck open over cools = no heat....