Hi I have an 89 YJ that is pumping cold air but the temp gauge is reading 210 degs. I just change the thermostat hoping to fix the problem but still having the same issue.
I think that there is either a clog or air lock but I'm not sure how to test it or fix. I was thinking of flushing the system but have never done that on this vehicle before. I've run the car with the radiator cap off and did not see any circulation of fluids. I also noticed that the hoses going and coming out of the firewall are cool.
It sounds like the heater core is plugged up. This it quite common on all vehicles. The passages in the heater core are smaller than a radiator's. You can test this by running one of the hater core hoses to the other connection on the engine. If the hose gets hot, then you know the restriction is in the core. If you do need a core, I would take the Jeep to a reputable shop that knows how to correctly flush a cooling system and have it flushed when you put the heater core in. For the future, I recommend using distilled water in your cooling system whenever possible (with antifreeze of course). This will cut down on the calcification that causes the heater core to plug up. My friend has a radiator repair shop and charges about $45 to flush a system and put in fresh antifreeze, so it shouldn't be too expensive to have it done where you live.
On both my CJ7 and my Cherokee I has really shitty heat. The Cherokee was even worse than the CJ!
In both of my cases, the heater hoses ran above the level of the fluid in the rad.
This makes for one sneaky air lock.
I dropped them down so they run below the fluid level in the rad and no more troubles, I have all it can give and then some in the CJ7.
In the CJ7 I put a monster GM blower motor from a 73 Blazer, 350, 4x4 with AC. It fits right in and the fan fits right on. Word of caution, one parts supplier in the US seems to have the wrong blower motor listed. The shaft is too long, so it is best to take yours with you so you get the right one. Here is a link on the upgrade:
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And before you go ripping dashes off to get to it, run a garden hose through it to see if it is actually plugged up or not. Try both heater core hose nipples, the in and out so it gets back flushed.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
With a flush kit, won't the water just take the path of least resistance? Going out the other end (radiator) and not unplugging the heater core? If the heater core is plugged wouldn't you need to put your hose right up to the heater core inlet? RMH
OK, I need to chime in here (again). The flushing kits you can buy in the stores are just about useless. they will remove the sludge and crud that is laying in the radiator or heater core, but they do nothing to remove the calcium and mineral deposits in these things. If you can't get water to flow through the heater core, just replace it. the core openings are so much smaller than a radiator core and they will scale up faster than a radiator. The radiator shops use a very diluted muriatic acid solution to attempt to remove the scale with the core or radiator removed from the vehicle, but the success rate is low. Again, the best way to prevent this is to use distilled water in your antifreeze mix. It should also be changed at least every other year. This is when the store bought flushing kits can be a small benefit.
Ok, Guys I fixed the Heat problem. I was a ble to flush the core and engine. After flushing everything until the water was clear bolted everything back and was tested. It all worked fine after the the flush. I has really good heat and the temp dropped from around 210 to
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