Malibu cabin heater not working
 

Heya,

My heater seems to have stopped blowing hot air. It's a 2007 Malibu vRide. It worked perfectly this spring, but won't blow a dang bit of hot air now.

I removed the pressure hose from the engine and water is pumping out of there just fine. I removed the return line at the engine and it seems to be pumping there just fine too. What the heck else could it be? I blew the line out in reverse and it seemed to blow out fine.

Any suggestions?

so hot water is getting to the core. But is the blower blowing?

Even at higher RPM? ie; 2000 or 2500?

Can you check the hose temp when the engine is running (and warm)?

What temp is your engine at?

Yes the blower is running just fine. I wasn't able to check it completely since I was by myself but the engine does get up to 160. I didn' run the engine up to 2000 since I didn't have a way of plugging off the return line where it plugs back in to the fresh water intake. I figured it was pretty basic, just wanted to make sure I wasn't missing something easy. I'll have to run it back down to the river with some help.

If the fan is running you should be getting air out the vents. If you are but are not getting heat it is just because the temperature is not getting up in the core.. That is usually caused by too low an RPM like Bill K suggested. If you run the engine above about 1600 RPM when the engine is warm you should get heat out of the core as it takes some pressure differential to get the flow through the long circuit of the heater. If you don't get heat then you have a blockage in your lines or core.

I agree, a blockage is most likely the culprit. I have the same problem now, just don't wanna get at the heater to fix it yet. Few other Malibu's I have had did the same thing. Usually just pull the hoses off at the core and engine, blow them out . Check the inlet at the core for small sticks and debris also.

Pulling those hoses off at the core is gonna be a major pain in the arse! I tried a bit a while back and it was a no go. I have a woofer there under the dash and it's right in the way of pulling those hoses.

Probably need to pull the woofer? Is it a pain to pull the whole box?

Yea, you'll need to pull the woofer. Mine has like 2 or 3 screws buried in the carpet across the bottom. Plus the trim piece on the left wide (aisle way wall). Then slide it out bottom first.

I have no idea the physics, but mine (2005 VLX) did this and the dealer told me to check the transmission cooler for weeds. Sure enough, I pulled out a handful of milfoil and the heat was back instantly. Took all of 2 minutes. Now I use the heaer as a guage, if it is not blowing very hot air, it is time to remove the weeds.

The weeds never cause the boat to run hot, but they do make the heater blow air that is basically "room temperature"

I'm sure I'll find it when I look at it, but where would you pull weeds out of the cooler at? I've drained it in the winter, but I don't see where I could actually pull anything out of it. Of course I'm not in front of it right now...

You should have basically the same engine as me. The hose runs from the water pump, goes down and thenhas an elbo (this is where your line to the heater will be) and runs back up towards the engine. You will have a metal tube, with oil lines going into and out of it. These lines are smaller than the water lines. Follow the water line to wher it connects to this metal tube (transmission oil cooler). Pull the hose and put a finger up their will be a metal screen. This is where weeds or debris would gather. Even if you find no weeds, it is good to check this from time to time as this is where impellar parts will be if your impeler fails or starts to come apart.

As you are facing the back of the boat, this should all be in the lower left hand side of the engine compartment, near the rear. If you remove you that engine panel on that side, you should have easy access. You may need to twist and and torque the hose to get it off the first time.

I found this picture. This cuts out the bottom which is the hose you want to remove. Hope it helps

Malibu's are bit different in that respect. The "hot" tube or output comes from the top of the intake manifold and runs to the heater core. The 'cold' or return tube dumps right back into the raw water pickup ,where there is a metal T installed that has a small orifice inside it to limit flow and keep hot water in the core longer. Nop screens that I have seen on the Indmar equipped boats I have had.