1995 Grand Cherokee Laredo 4.0 2WD underheating?

Thermostats haven't changed since they were introduced.

If your heat is good then the system is working, it's the sensor or connector that's buggered up. Putting a hand on the upper radiator hose will tell you if the engine is warm and coolant flowing. just give it a bit of a squeeze and you can feel the coolant rush.

The other option is with a cold engine, just take the radiator cap off and start it. There will be some flow and as soon as the engine warms up a whole lot more.

I'd pull and check the connector. Also check the wire to make sure it didn't get pinched or chafed while doing the radiator.

Right now I'd bet the thermostat is fine and the problem is electrical.

On 02/21/2009 08:12 AM, DougW wrote: [snips]

Thanks, I'll check in a day or two (woke up with a bad cold, so the jeep will have wait) & post back on what I find.

Neither the temp gage senders nor the thermostats are particularly reliable in use or even out of the box.

You can get a n> Leak on the original radiator prompted a replacement which was replaced > by my son:

Thanks for the replys. Here is the current status:

Rain finally stopped & my cold subsided enough to go pull the thermostat (haven't installed the new one yet, hence the 'Revolved - partially' tag.

Apparently thermostats aren't made the way they were 30-40 years ago - I miss the days of thermostats in the radiator neck... After finally finding the right socket-extension combination to allow me to get the lower thermostat housing bolt off (belt hits it midway so it's a real pain to find just the right size between the fan and just enough to push down the belt), I pull the housing. See the thermostat plate, pull it, and find that only the plate comes off... the rest of the old thermostat (spring et all) is inside the block! The damn thing had fallen apart! I've never seen anything like this before.

Thermostat Plate | | ====== spring/element |

Called my son & he said that he'd gotten it at Autozone . I've a mind to take all the bits an stick it up Autozone's bin. Update... he just called the guy at Autozone and the guy there say's 'Dude, you're the third guy that reported this happening this month!'... dude. I can't tell what it is any longer, but _think_ it was a Valuecraft Part Number: 3009 Weight: 0.15 lbs. Note: 195 degrees

Anyway, cleaned the housing, sanded the face where the gasket will go, and getting ready to replace with a new thermostat. Remaining questions are:

1. I've two new thermostats that I can put in - 1 a 180degree (Duralast) and the other a 195degree (Stant) - don't ask why I have two... let's just say I sent someone to 'go pick up a 95 GCL thermostat and they returned with two). So aside from brand, which is the better to put in, the 180 or the 195? I think the 195 is the oem recommendation, but I read somewhere that the lower 180 gives added horsepower and gas mileage... wives tale?
2. The sensor unit in the thermostat housing is stuck. Meaning that I can't reasonably unscrew it from the housing for fear of breaking something. The sensor is probably good (given the thermostat issue), but I'm just wondering if it's worth the effort install as is, or just get a new housing (housing unit looks fine once I cleaned it up w/gass & fine grit sandpaper) and sensor and stick those in instead?

New thermostat (Stant 195) is in, all is working well again. Temp is back up to just below the 210 mark after warming up and taken for a long test drive.

Sounds like yo are back on the road. Nice feeling.

You do not want to use the 180 degree thermostat. The eng> >