Engine stays cold

[2ndMDRebel]

Please bear with me and hear my tale of woe...

My car is currently having a problem with the cooling system. When the ambient air temps are below 40 degrees the car will not get to operating temperature on my drive to/from work. I always let the engine sit and idle for 3 to 5 minutes before leaving and the drive itself is roughly 1 mile to the highway, 8 miles on the highway, and another mile to the destination, total about 10.5 give or take a tenth. Depending on lights and traffic its usually about 15-25 minutes. The coolant temp gauge will barely reach the lower line on the "normal" range and unless I take the OD off and dog the heck out of it it won't get to the correct level. When the temps are above 40 or so, the temp display will be a tad bit higher but still below where it normally runs. I have heat, not hot but passable, and there is no air that I can tell in the system. This is what's happening now.

Now for the recent history...

The whole situation started last November when the t-stat evidently got stuck closed and the car was blowing coolant from the top of the reservoir. Had it towed from the racetrack. My tech tested for exhaust gasses in the coolant and it showed negative so he replaced the t-stat but it would run in the upper part of the "normal" range and there was no heat from the vents. Air pocket. I got another t-stat and this time he drilled two small holes in it to help with the air bleeding and we replaced it and bled the air out. I also replaced the pressure cap on the reservoir. The original t-stat the engine came with from Lidio was a 180 degree also drilled, the first one my tech put in was a 195 deg and now it has a 188 degree t-stat in it.

I don't know what to do or where to go at this point. My techs are done with the car and don't want to mess with it anymore. I don't want to drive it because its not working right and I'm afraid of causing damage. Any advise or suggestions?

[merc]

Where are you reading the temperature from? I found that the factory Hot/Cold meter is not very accurate. I read my temps from the AeroForce gauge I have on the A pillar. When racing I notice a 20 degree swing that is not shown on the cockpit display. That being said, try to find another way to verify the temperatures you are seeing.

[RF Overlord]

The fact that you have luke-warm heat and the gauge reads low, I'd say you have a thermostat that's stuck open. This happened to me on my company-owned work van. Exactly the same symptoms. I replaced the 'stat and all was well.

That "UFO module" the thermostat sits in is a little weird. Perhaps the new 'stat was put in upside-down? Maybe he put the o-ring in wrong? Maybe the new 'stat is just plain bad? I don't think drilling holes in it was a good idea. That's generally only valid when the thermostat is the highest point in the cooling system. If it needed them, it would have come with the little dingly thing already installed. Bleeding is supposed to be done from the bung in the cross-over tube, not from the thermostat.

[JohnPPD]

^^^^+1^^^^

Sounds like an open thermostat, or the symptoms of removing the thermostat all together. If the computer reads the coolant as cold, it may begin to feed it a little extra fuel and you'll run rich. I had that happen in another car before and it was a royal PITA with the plugs and carbon build up.

[Blackened300a]

That problem sounds most like a stuck open thermostat.

[finster101]

I have to agree with a stuck open T-stat. Two small holes will not provide enough flow to keep the car cold. I would only put one in it when you replace though, that is plenty if t***** air is your concern.

[jgc61sr2002]

That problem sounds most like a stuck open thermostat.



I concur.^^^^^^

[Dennis Reinhart]

I would start with a stock T stat, by drilling holes in the T stat you are allowing for coolant to flow even before it opens up, so this is not allowing coolant to stay in the block to reach a good operating range, this can can cause the car to run to cold in the winter and run warmer in the summer, the old wives tail about taking out a T stat will make a car run cooler is wrong, for the same reasons described above, coolant will flow to quickly through the radiator, to allow for the air passing through the radiator to remove the heat from the watter.

[Vortech347]

x4, bad T-stat.

[2ndMDRebel]

The thermostat wasn't bad, it was just wrong. Sometimes I empathize with people that hate dealerships... but anyway...

The ticket I wrote on the car was for a 2003 Crown Vic so what did my parts dept do when I asked them for a Marauder t-stat? They game me a stock CV t-stat which was the wrong temp range... the second t-stat that went in was from AutoZone and what did they give me when I asked for a Marauder t-stat? They gave me a t-stat for a CV but a little cooler temp range. See, I didn't realize that there was a real difference because all the "experts" in my parts dept and AutoZone were telling me they were the same. I PM'd Lidio and he told me he uses stock t-stats which got me thinking, so I looked up the workshop manual online in OASIS and saw that the Marauder specs for the t-stat were different after all, then I went to the parts dept armed with my wife's VIN and we sat there and looked it up on the computer and low and behold the Marauder has a special part # separate from the Crown Vic, even has "Thermostat (Marauder)" in the name! Got that ordered and installed and voila! No more staying cold, engine heats up to normal operating temperature, getting good heat from the vents, and I have my car back! We compared the two and the Marauder has a wider base which plugs the upper hose whereas the others had small bases which let the coolant flow. I don't care how it works, just that it works right!

[Master]

Very cool information. Good work. I was about to say x5 on a bad stat since I just went through that on the F-350 ($30 and 20 minutes - easiest fix I've done in years). Glad you are rolling again!

[Dennis Reinhart]

The thermostat wasn't bad, it was just wrong. Sometimes I empathize with people that hate dealerships... but anyway...

The ticket I wrote on the car was for a 2003 Crown Vic so what did my parts dept do when I asked them for a Marauder t-stat? They game me a stock CV t-stat which was the wrong temp range... the second t-stat that went in was from AutoZone and what did they give me when I asked for a Marauder t-stat? They gave me a t-stat for a CV but a little cooler temp range. See, I didn't realize that there was a real difference because all the "experts" in my parts dept and AutoZone were telling me they were the same. I PM'd Lidio and he told me he uses stock t-stats which got me thinking, so I looked up the workshop manual online in OASIS and saw that the Marauder specs for the t-stat were different after all, then I went to the parts dept armed with my wife's VIN and we sat there and looked it up on the computer and low and behold the Marauder has a special part # separate from the Crown Vic, even has "Thermostat (Marauder)" in the name! Got that ordered and installed and voila! No more staying cold, engine heats up to normal operating temperature, getting good heat from the vents, and I have my car back! We compared the two and the Marauder has a wider base which plugs the upper hose whereas the others had small bases which let the coolant flow. I don't care how it works, just that it works right!


Well I believe I hit the nail on the head< I am glad you got it fixed,

I would start with a stock T stat, by drilling holes in the T stat you are allowing for coolant to flow even before it opens up, so this is not allowing coolant to stay in the block to reach a good operating range, this can can cause the car to run to cold in the winter and run warmer in the summer, the old wives tail about taking out a T stat will make a car run cooler is wrong, for the same reasons described above, coolant will flow to quickly through the radiator, to allow for the air passing through the radiator to remove the heat from the watter.

[2ndMDRebel]

... the correct part # is F5OY*8575*A for the Marauder 'stat just in case anyone may need it.

Funny thing is the same thing happened to my wife's car, the real Marauder, back in Aug, brought it in for engine taking too long to heat up and they installed a 7L3Z*8575*B which is a 2v GM thermostat. It wasn't until the heated seats quit working that she told me the engine was still taking forever to warm up. Now I've got the correct one on order as well as the heated seat stuff. Momma ain't happy when she's cold!

[DTRMiguel]

Momma ain't happy when she's cold!

LMAO :rofl: neither is mine ask your wife she met my mother at the track that day :D

[ace7]

The other day I installed a new thermostate on my 03 MM, and I installed the pointy part of the thermostate facing down towards the ground, and the spring loaded end facing up. was this the correct way? My engine does not seem to be warming up right away when I start up in the morning to warm up. Please help. Thanks

[Guittard22]

This happens on my vic it takes about 20-30 min for the car to heat up and oil ??

[fastblackmerc]

The other day I installed a new thermostate on my 03 MM, and I installed the pointy part of the thermostate facing down towards the ground, and the spring loaded end facing up. was this the correct way? My engine does not seem to be warming up right away when I start up in the morning to warm up. Please help. Thanks

You install a new thermostat the same way the old one came out.