Hi
My engine over heated,loss of all coolant.No engine lights came on and no codes showing.When I fill the expansion tank the wated pours out the rear of engine onto gearbox quicker than I can put it in.
It's x150 2006 N/A.Can anybody point me in the right direction as to the cause.
​​​​​​​ Thanks. Tommy.

 

Back of engine
Please be more specific so we can narrow it down for you

Could be head gasket, cracked block, welch plug, heater hose etc

 

+1
You need to look a little closer to narrow it down.
Could be the expansion tank itself, it has been known to break, that plastic is over 10 years old now.

 

It's hard to narrow it down.As said the water pours out down both sides of the valley in between the v at rear of engine.Switched engine off at 101 degree as have a guage fitted.Engine starts and runs fine.
Thanks for helping Tommy.

 

Happened to me but luckily it started to leak once i pulled into the parking bay at work so no damage, all coolant drained out, used water to test and poured out as quick as putting into.
As you are aware a jag fault with no temperature gauge, so once the light come on you've had it, too late.
Mine is an xkr and under the supercharger is 2 coolant pipes that lead from front to back, one of mine busted and the coolant was leaking like yours to the back of the engine, that's the way it will flows due to the way the pipes run. Got it brought away buy transporter and 2 new pipes and coolant on.

Same 2 pipes might be running the same on your car , only difference they won't be under a supercharger like mine, so maybe down under your cover.

You should have the thermostat changed as well as the rubber seal turn on itself over time and does not work properly.

Put a post up some time ago about this issue about changing the fatigue pipes and thermostat on the early cars , but i suppose some people don't bother taking the advice till it's too late. Have got several advice on things on this site and acted on them.

 

Yes I changed the thermostat and housing 6 months ago so at least I took half the advice that has been offered just not the other half.Hope the engine has not been damaged, like you noticed it while parking and then had car recovered on truck.
Hope to fix it myself.
​​​​​​​Thanks for helping Tommy.

 

Page 1157 of the '07 service manual shows the coolant lines on a ghost picture of the engine. There is a little one that feeds the throttle body #9 (so it doesn't freeze up) and that's the common one to fail. There's also a heater manifold #10 back there hat looks like it ties other coolant stuff together back there.

A small inspection mirror and flashlight might let you see where it's coming from but either way the intake is coming apart to access that hose.

 

Thankyou for that information,it's very helpful.

 

Overheated is a broad term. Loss of coolant and steam doesn't necessarily mean the engine overheated. I realize because there is no temp gauge the only warning would be the red engine light but if it doesn't turn on but yet you see steam it may not over temped as you shut it down in time before the warning came on. Dangerous overheating is in the 240* F + range. Coolant hitting a hot manifold at 200*F will produce smoke.

 

Thanks Jagtoes will update when I start stripping it down .

 

I just got back from a 1/2 hour fuel run. Plugged the Torque pro in and kept a curious eye on temp and voltage. Mind you it is 73*F here and sunny today so on the open road it runs at 194*F-199*F and in traffic it's 198*F to 204*F. Voltage running from 12.9V to 13.7V looking at it from the control module . So this is the 5.0L S/C . What it makes me wonder and what I have to look up is what the value of the thermostat is.

 

I have a temperature gauge that reads and displays engine temp via the OBD port on my 5.0L NA. I have similar open road temperatures ~190 to 200F, irregardless of ambient temp. Stopped in traffic at a stop light it has gotten up to 221F with 105F ambient. I was surprised that it gets that hot. I want to see where the temperature sensor is located to see if it is measuring the block temperature or water temperature and compare this maximum temperature to my other cars.

 

As an FYI my new 5.3L chevy truck WT runs at 210*F all the time.

 

OK I found it. The thermostat starts to open at 190*F and is fully open at 216*F. Anywhere in that range is OK. There is a low coolant level sensor in the bottom of the expansion tank. This is wired directly to the message center in the gauge cluster (where the fuel gauge is) . You get 2 warnings , 1 when the coolant tank is low and the other is when the engine temp reaches a limit set in the ECU. I don't know what that temperature is but it should be below a catastrophic failure.

 

0n the 4.2L engine, the engine coolant temp sensor is on the pipe-outlet which is a black plastic pipe mounted to the intake manifold and coolant pump bypass. The radiator hoses also are attached to this plastic pipe. The engine thermostat is located on one end of the pipe.

 

Found out the Amber warning light comes on at 118°~119.3.Red triangle comes on at 119.4 ° and above.As I had complete coolant loss does this mean the tempature is no longer monitored. ?.
​​​​​​​ Tommy.

 

Since the water pump is above the coolant temperature sensor (CTS) it is probable that the water pump was running dry and not pumping any coolant through the cylinder jackets and heads to be heated and the temperature measured by the CTS. If the coolant loss was rapid, such as from a burst hose, I could see it taking awhile for the CTS to get hot enough to issue the warnings.

 

Hoping I caught mine early enough to save the engine as I had no warning lights showing,although coolant loss was rapid .I did have temp guage fitted through obd port and was showing 101°when engine was switched off but wheather this was true engine temp who knows.

 

For us Americans, Tommy's data says that the amber warning light comes on at ~ 244 degrees F and the red triangle comes on at ~247 degrees F. With a 14 psi radiator cap and 50/50 antifreeze solution the coolant should boil around 265 degrees F. The warning lights give a SMALL amount of margin.

 

The 101 degree temperature from the obd port *should* be coming form the CTS. That is the only coolant temperature sensor I could find. Under normal operating conditions mine gets hotter than that.

Will the coolant reservoir and "low coolant warning" light illminate with a rapid loss of coolant?