NO heat or at least little heat

ok, 87 xj 4.0
took it out for the first time playing in snow (another post for the results of that) anyway, the engine had plenty of time to get to full heat, still a little low if you ask me. The heater full crank and it wasn't even hot? I stopped and rev'd it to 3k and I couls feel heat. What is my problem?

what did the engine temp get up to?

your heater core is prolly all clogged up...

do a search on here...lots of good info on how to flush out your cooling system

Not sure exactly what temp it got to but I know it was low, especially for how I was driving. Should have been higher. It has been sitting for a year, I bet it needs a flushing. I know the local quicky lube place does it for $60

I had the same problem in my 90 same closed style. regular shop flushes wont do it. You need to remove the heater hoses and backflush the heater core. I did this and now I have heat. Mine went from NO heat at all to full on heat just with that. Mine had been recently flushed at the dealer with all new coolant and was very suprised at the brown nastyness that came out! a common coolant flush doesnt put enought pressure through it especially with the pressure bottle taking some of the flow.

The heater control valve goes bad in the XJ regularly. Make sure that its not the problem...though usually it goes bad and allows heat all the time..but I have seen it rust/seize in the closed or partially obstructed state. Also make sur the vacuum line is connected to it. Dont expect much heat evne when all is well, early XJs are not the best in the HVAC dept.

XJguy

I did a search and found a link to a do it yourself heater core flush, i might try this but it needs to warm up a bit here first....wait then i won't need all the heat! ARGE!

No Heat

1. Check all the vacum lines starting from the cannister behind the front bmper
(passenger side) all the way to the firewall.
2.Until you get it flushed,keep an eye on the temp guage.

I had this problem on my 93 with an open system. At idle, even after the engine had been running for an hour, the air would blow luke warm at best. As soon as you step on the gas, the air is noticeably hotter, right? Flushing the heater core is always a good idea, but for me it was as simple as antifreeze. Whoever owned this before me must've filled up the overflow with mixable antifreeze without mixing it (it was neon frickin green). Draining the overflow, filling with distilled water, then running the engine for an hour to mix it up fixed my problem. The antifreeze was just too heavy for the pump. This is in MI, by the way, so I know how cold you must be--i hope you find a solution.

mark268 said:

I did a search and found a link to a do it yourself heater core flush, i might try this but it needs to warm up a bit here first....wait then i won't need all the heat! ARGE!

Click to expand...

I had a local shop do a heater core flush for $20. I do most of my own work but sometimes it's just not worth it.