1994 Jeep Grand Cherokee Limited 5.2L ... When it got cold here in Michigan, I noticed that i didn't have very much heat coming out. Operating temp was normal. I changed the thermostat...Still no heat (just warm enough to keep the windshield from fogging) and engine temp is higher than normal. I then noticed the water pump leaking so I replaced it. I had been smelling coolant around the front of the vehicle when it was hot but had no leak until now.
Now, still no heat and my engine temp was running as high as 235! Bad thermostat? Air pocket in the system? Another thermostat (195) and also bled the system. Engine temp now a little lower (220) but still no heat.
Engine gets hotter the fast I drive than slow or at idle. Always fluctuates.
Bad flow? Back flushed the heater core (dramatic difference in temperatures between the inlet and outlet heater hoses) and got a crap ton of junk and gunk out of it. Still, no change.
Still bad flow? Radiator? Flushed and got yet more junk out of it. No change. Replaced radiator.
Now, still smell that coolant more so on the passenger side when hot but no leaks. Runs at around 210 to 220 after warm up. No heat still. No bubbling at the neck of the radiator. So far, no loss in coolant. No milky oil. No white smoke from tail pipe.
The only thing I am now down to is head gasket??? You can tell the thermostat is working correctly. I have not yet done a leak down test or compression test on each cylinder.
Anyone have any thoughts or ideas?
Severely irritated as this is my primary and only vehicle. I drive over 70 miles a day for work... UGH
Thank you in advance.
ps. I wish I could change my username as I no longer have my Wrangler. lol
hate to ask but what about the heater core? some times they get clogged and itll cause an over heating issue, best way i have heard to flush the core is to open the drains and put a garden hose in the radiator and let the water flow, itll be messy but with it just being water shouldnt hurt much of anything just suck loosing out on more antifreeze
2004 Lexus Es330, alive; 1999 Cherokee Sport
1998 Grand Cherokee, sold
1997 Grand Cherokee; Black and Gold, Limited 4.0....RIP 2005
to the good times and the bad, the family we have and lost, little brother 1988-2011
Well I know it isn't the head gaskets, intake, radiator, thermostat, hoses, etc because I just replaced ALL of them. lol I also back flushed and flushed the entire system. I directly back flushed the heater core also running water through it for quite a while. SEEMED to flow just fine. While the engine was torn down, I blew all of the water jackets out and it was nothing but milky gunk telling me there was definitely some water seaping in there. Head gaskets looked OK but definitely saw signs for concern so it wasn't a wasted job.
So here's my thinking. It never ran hot until replacing the water pump so I think I have a bum reman water pump. Here's another sign. After driving and letting it get hot, I drained the radiator and the coolant initially came out cold for a couple seconds then came out steaming hot. This tells me that it is not flowing well at all. As for the heat, it definitely could be the heater core. Could also be a heat door or something... ???
Maybe some of the core tubes are clogged, so that only a fraction of the heater core is actually receiving hot water. I think if you got slightly warm air on the lowest fan setting, and cold air on high, that would be be an indicator of this possibility.
A quick test to determine if the pump is working is
to check if the heater warms properly. A defective
water pump will not be able to circulate heated coolant
through the long heater hose to the heater core.
5.2/5.9L ENGINES: One of the heater hoses is
connected to the water pump with a metal coolant
return tube (Fig. 9). A rubber o-ring forms a seal at
the water pump end of the tube.
WATER PUMP TESTS
DO NOT WASTE reusable coolant. If solution is
clean, drain coolant into a clean container for reuse.
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR
DRAINCOCK WITH THE SYSTEM HOT AND UNDER
PRESSURE. SERIOUS BURNS FROM THE COOLANT
(1) Drain the cooling system. Refer to Draining
Cooling System in this group.
(2) Loosen the fan belt. Refer to Belt Service in the
Engine Accessory Drive Belt section of this group.
(3) Disconnect the lower radiator hose from the
(4) Bend a stiff welding rod or similar device as
shown in (Fig. 16). To prevent breakage of rod, minimum
thickness should be 3/16 inch (.187 inches).
(5) Position the rod in the water pump inlet and
attempt to hold the impeller while turning the fan
pulley. If equipped with a thermal viscous fan drive,
rotate the water pump shaft with a wrench attached
to one of the fan pulley mounting nuts. If the impeller
is loose and can be held with the rod while the
fan blades are turning, the pump is defective. Do not
use excessive force when rotating pump shaft. If the
impeller turns, the pump is OK.
(6) Connect the hose and install the coolant, or
proceed with repairs.