350MJ Posted February 8, 2014 Share Posted February 8, 2014 Never noticed until this winter, heater isn't hot enough. Not really complaining but this winter is rather chilly. My truck's heater get warm it's not broken. It gets hot enough to defrost the windows but not enough to keep the cab warm the entire time. Especially when I'm on the highway it can't heat up the cab enough. Anyone know how to increase the heat coming out. Not just the air flow I mean the temperature. Link to comment Share on other sites More sharing options...
nitroxsteve Posted February 8, 2014 Share Posted February 8, 2014 What temp is your engine running? If the engine is running the correct temperature but still no heat you probably need to back flush the heater core. It's a fairly common problem. Link to comment Share on other sites More sharing options...
Blaine Posted February 8, 2014 Share Posted February 8, 2014 i agree is it a 2.5 or 4.0? also just learned about this, in the pic below the heater valve is vacc. operated amd sometimes doesn't let coolant into the core and it bypasses through the jug and back to your w-pump. it does this when heat is not in use. sometimes it gets finicky and doesn't work when its supposed too. if flushing the core don't work this could very well be the problem. 6 cyl. 4.0 style. Link to comment Share on other sites More sharing options...
NHMJXJ Posted February 8, 2014 Share Posted February 8, 2014 Start simple. Are you reaching proper operating temp? Do you have the right coolant mix? Link to comment Share on other sites More sharing options...
hassyfoto Posted February 9, 2014 Share Posted February 9, 2014 As already stated, start simple. Check to make sure you have: 1. The correct type & amount of coolant- a low coolant level can cause lack of heat issues 2. Heater valve is functioning correctly ( already stated by Blaine) 3. Heater controls are functioning properly- sometimes the controls are not functioning properly allowing the heater box to switch from defrost to heat, etc. 4. You have the correct thermostat ( many folks place a lower temp thermostat in vehicles) 5. Water pump is not working correctly- a corroded or non functioning impeller on the water pump will result in lack of water flow. What is the current operating temp of the truck andhas it raisin recently. 6. Flush coolant system ( a clogged hose, heater core or non-functioning heater valve) 7. Heater hose(s) are old, have collapsed internally and warrant replacement 7. Heater core is clogged, replacement warranted Link to comment Share on other sites More sharing options...
350MJ Posted February 9, 2014 Author Share Posted February 9, 2014 thanks guys ill have to look into it in the morning.It does work i mean it defrosts well just this winters cold makes it a bear to drive in. I don't want to be sinking too much into this engine because its getting replaced this spring for a chevy 350. more power than my little 2.8L. thanks again i'll end up looking through it tomorrow before i head back to college. Link to comment Share on other sites More sharing options...
rullemj Posted February 9, 2014 Share Posted February 9, 2014 Temporary fix would be covering up the grille with some cardboard. Not uncommon to do here in Sweden during winter. Link to comment Share on other sites More sharing options...
nitroxsteve Posted February 9, 2014 Share Posted February 9, 2014 Temporary fix would be covering up the grille with some cardboard. Not uncommon to do here in Sweden during winter. this will only help if his water temp is low like with a stuck open or too low thermostat. Link to comment Share on other sites More sharing options...
Lee21490 Posted February 10, 2014 Share Posted February 10, 2014 Could just insulate the truck better, So it stays warmer easier in the winter. For under $100 you can do your entire cab with "Frost king" Foil covered Closed cell rubber matting, (Poor mans dynomat) From home depot Helps quite your cab from road noise, Also helps to insulate the cab from cold. Link to comment Share on other sites More sharing options...
Jeep Driver Posted February 10, 2014 Share Posted February 10, 2014 I'm now running a 180 stat, does not get nearly as hot inside as it did with the 195........but engine temp is now constant. Link to comment Share on other sites More sharing options...
gogmorgo Posted February 10, 2014 Share Posted February 10, 2014 Could just insulate the truck better, So it stays warmer easier in the winter. This. My heater works great, but my door seals aren't so hot. If the wind's blowing from the wrong direction the side of my left side gets a little chilly. I also once got a cold breeze at the back of my neck, and I suspect it had something to do with the b-pillar cab vent, but I can't be sure. Link to comment Share on other sites More sharing options...
rullemj Posted February 12, 2014 Share Posted February 12, 2014 Cab vents are simply decorative, unfortunetly. You have a split rear window? Link to comment Share on other sites More sharing options...
gogmorgo Posted February 12, 2014 Share Posted February 12, 2014 Yes I do have a split window, but I'd have to disagree with you on the decorativeness of the b-pillar vents. When I've got my truck running with the heat on, there's warm air coming out of the cab vents. In order to be able to close the doors easily, there has to be some way to relieve the pressure built up from slamming a door shut. There also has to be somewhere for air to escape so the heater/ac can continue delivering fresh air. On the XJ the vents are in the rear hatch (I think). MJ's have no rear hatch, so the solution was putting vents in the b-pillars. Link to comment Share on other sites More sharing options...
rullemj Posted February 12, 2014 Share Posted February 12, 2014 Interesting. Pulled mine (just one side) to fix a dent left by the PO couple months ago :shake: Was surprised because I found no ventilation opening, just solid metal. Not saying you're wrong, but at least on mine there's no vent-opening beneath the plastic. Checked so the rear window's got a good seal?Just an idea when you mentioned the cool air hitting the back of your neck. My 88's really bad around the doors, the rubber-seal's been worn to shreds from freezing against the metal and being "ripped" when opening the doors. Have to fix that some day :rolleyes: Link to comment Share on other sites More sharing options...
gogmorgo Posted February 12, 2014 Share Posted February 12, 2014 Which side did you pull off? The driver's side definitely vents, don't know that the passenger side does, though. I get no heat out of it. Check out this thread. This pic has a whole lotta crazy going on, but you should still be able to see where there's a very obvious vent in the MJ b-pillar. Link to comment Share on other sites More sharing options...
rullemj Posted February 13, 2014 Share Posted February 13, 2014 Was the pass-side. If nothing else it's great that they're actually functional. Link to comment Share on other sites More sharing options...
350MJ Posted February 24, 2014 Author Share Posted February 24, 2014 I think they differ per year too. I've seen a 1990 that there were no vents behind it but my 86 has a vent behind it. Different technology through the years might have made that change but they kept it for looks because it distinguished the MJ. As far as my tuck being cold guys it fixed its self i think it was just because of the negative 30s compared to the teens we have now. Link to comment Share on other sites More sharing options...
JeepcoMJ Posted February 24, 2014 Share Posted February 24, 2014 All mj have vents unless removed during body work, or someone forgetful/lazy was on the assembly line that day. Link to comment Share on other sites More sharing options...
HOrnbrod Posted February 25, 2014 Share Posted February 25, 2014 I just checked put the B-pillar panels in my MJ body parts manual. All domestic (N. America) MJ had vents on both sides with a rubber flapper valve under the exterior panel to supposedly allow air out of the cab but nor in. But it's just a rubber piece, and most have probably disintegrated away. Also, some of the export models had an extra sheet metal reinforcement piece in the B panel, that probably means there was no vent in some of them. Link to comment Share on other sites More sharing options...
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