Hello all, I really appreciate this forum, it has helped me out many times, but this time I am making my first post, due to the fact that I'm stumped on this one...

So first of all it's my wife's car she has a 2002 X type with a 2.5L. A few months back it overheated and someone had looked at it and thought the radiator was leaking, so we ordered a new one, along with a new coolant recovery tank. Well turned out it was the thermostat housing that had cracked! So ordered the entire part with a new Thermostat.

And after I put the new Thermostat and housing and hose in all was perfect, no leaks it ran just fine.

So the other day she called me and it had overheated again so I had it towed home and after looking at everything I noticed the coolant recovery tank had cracked in a couple place's so I figured that's why it didn't have any coolant in it so it was the cause of it overheating. Ordered a new tank (again) and I also ordered a new water pump since it's real simple to change.

So now this X type has a new radiator, thermostat (plus housing), and a new water pump. Started it up let it idle until it reached opp temp. So tooking around the block and it overheated again!!!

I'm worried it could be the head gasket? But it is not leaking coolant anywhere, the oil looks fine, there is no smoke coming out the exhaust, So I'm still thinking it could be the head gasket. Or could the thermostat have failed already??

A couple of other things when it was idling and I'd give it some gas the coolant in the recovery tank would go down a little bit then come back to where it was when you'd take your foot off the gas, also it would release some bubbles, I thought it was just the system getting all the air out, but now I'm thinking it could be because of a failed head gasket???? Any ideas??

 

Engine coolant temperature sensor?

Symptoms of a Bad Coolant Temperature Sensor

Overheating Engine

If you notice that your engine overheats, the coolant temperature sensor could be the problem. At times, the coolant temperature switch may fail such that it starts transmitting hot signals permanently.

 

Bad head gasket wouldn’t cause engine overheating unless it is so bad that it leaked out a lot of coolant…and you’d see that…and the motor would run bad. I’d try what @Dell Gailey suggested.

 

Did you notice if the fans were spinning fast and blowing alot of air?

 

One of the best tools I own is a cooling system pressure test. You can often rent one. Will tell you a lot quickly.

 

Yes the fans were on and producing a lot of air. They also stayed on after the car was shut off. The fans seemed like they turned on sooner then they did before but I just figured it was from the 100 degree weather we have been having.

 

I have some more info, on the problem (over heating). The check engine light has been on, it has needed a knock sensor (P0333) but I decided to check for anything else that might have shown up. (and there was).

I have a misfire in cylinders 1,3,4,&5. (P0301,P0303,P0304,P0305)

The car seems to run the same as before those codes showed up, I asked my wife and she said on one occasion the message center thing said Cruise Control is Off or something like that, she said she has never even used the cruise control but the car was was not running right the way she described it I thought it sounded like it was in limp mode or something. But it stopped after she had parked and shut off the car and when she left the car was fine again.

I know I have needed to replace that knock sensor would the new codes have anything to do with the over heating? I know when the knock sensor is bad the car will retard the timing I think, I was thinking that could be why it misfires.

Well I plan on pulling the thermostat out and testing it to make sure it opens, but I will replace the coolant temp sensor and see how that works out.

 

Is that pressure test tool the same as the ones you pull a vacuum on and refill the coolant system? Or is it the ones that come with a pump?

Also what is the normal operating PSI for the cooling system??

 

Quick question about the coolant temp sensor if it is bad then does it show false high temps? Like the red light on, and gauge showing H and the fans staying on after you shut off the car??? The engine seemed pretty hot, but like I said it's been 100 degree temps around here. So that might have been why. And my wife knows to pull over right away and to turn the heater on full blast to try to cool the engine down somewhat.

 

So if everything is working correctly the fans DO NOT continue to run at shut off. That was the fault I encountered when my FCM failed out of no where. Drove to store, shut off car and fans remained running. I thought "well that's odd and new". Came back out 20-30 minutes later and fans still running. Got a FCM from member Dr Dome. Replaced the FCM and all has been well since and fans have NEVER remained running on shut down.

If the coolant temperature sensor is bad, yes it can falsely tell the car it's Overheating with accompanying guage and Overheating light.

Pressure testing =

https://crawfordsautoservice.com/how...ooling-system/

 

I'm going to replace the Coolant Temp Sensor tomorrow. We will see what that will do.

Also I was letting it idle last night to operating temp and I have my code reader plugged in (Bluetooth) and the app I use has a dashboard feature with a Temp Gauge and my fans came on at 203 degrees. Another thing was the temp just kept rising the hole time, it never dropped down when the Thermostat should of opened, and I'm not sure but doesn't the temp also drop down when the fans engage?

Well the temp just kept rising at steady pace until it got in the RED about 234 - 237 degrees then I shut off the car. But the whole time my gauge on the dash of the car stayed in the middle of C and H.

So I'm going to try a new sensor and I'm going to take the thermostat out and test it.

 

FIXED IT!!!!
Last night I decided to take out the thermostat to test it even though it had just been replaced a few months back when I had to replace the whole thermostat housing that had cracked (plastic) and it also came with a new thermostat.
Well to my surprise when I removed the 3 bolts to pull out the thermostat, it came out in pieces!! Apparently one of the 2 plastic tabs that hold the spring compressed had busted and caused it to just come apart somehow keeping it closed. Really sucks since that thermostat and its plastic housing cost over $100! for plastic.

Thank you to all who replied to this post. I'll try to post a pic.

 

 

I'm a bit late. Sorry to say this, but the first thing we do in such a case is to check the newly installed part. It can happen that these parts are installed under tension or at an angle and then they block. Or, as in your case, they simply give up the ghost after the first use. We've already had both of these happen at least twice.

 

Wow! That's certainly a dandy!