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Hello everyone;
We have a '03 Discovery II in the shop and after replacing the engine, radiator, water pump, every coolant hose and thermostat now we realize that the thermostat is not opening. The hose between the Thermostat and the radiator is cool while the other two (to water pump & to block/radiator) and hot. Scanner reads engine temps at 245deg and the gauge neddle keeps going up.
All the work has been performed by ALL DATA and we can't figure why the thermostat doesn't open.
Figure best to ask as you guys as you know your trucks better than any book.
Obviously the coolant is not being pumped through the engine.
I would say it is a bad water pump or the fan belt is on wrong.
Also make sure the t-stat is installed in the correct direction.
- bad water pump
Check = is Brand New
- the fan belt is on wrong
Double Check = is good
-t-stat is installed in the correct direction
Double Check = had it installed in correct direction in two different ways
By the way the thermostat's brand is Colorstat by Vernet and we are on the second one
I hope they are not picking up the cost of all that stuff.
but rule number one, if aftermarket crap doesn't work then buy the dealer. always.
and what did it come for in the first place.
Hello Rovin4life:
The truck arrived at our shop on a Flatbed Towtruck, at the beginning we were told that the engine gave up, but now we've being told it might have overheated. The customer brought us an engine and told us they were planing on a major tune-up anyways.
The sad part is that the owner had just bought the truck and after some 35 miles driving it home it broke. So yes they are paying for everything but was expected anyways.
Now the thermostat we installed is the same brand as the one the truck came with and bought from the same supplier. My question is: How often these trucks encounter thermostat quality problems, and where we can buy an OEM part?
You can buy one from Rovers North or Atlantic British, or a dealer. If the cooling system has stop leak running in it, it can stop up small metering holes in the top of the stat that allow hot water to enter, operate the stat, and make it open. It depends on flow through the bypass circuit. Heater core could also be plugged up contributing to this, you should test heater core for flow in/out, or just bypass it by a length of hose to take it out of the circuit.
Cold from bottom radiator hose in the bottom, when open that moves out the "arm" to the water pump. The hot coolant sample moves down the top axial opening. Normal for top two hoses to be warm as coolant flow at metering rate is always underway. IMHO, the dang metering holes are too few in number, but that is just my opinion.
Flow chart attached.
There have been posts of brand new ones failing to open. One DIY used hot water from a tea pot to test his.
The spec for a factory stat is start to open at 180F, full open at 204F. It is an inverted bypass stat, that plate with the holes in the top can move down by pressure when the main stat is not open when engine is revved up. So the idea of tripple checking the water pump rotation direction is a good one. It is reverse direction, facing the engine, it should turn counter clockwise.
You are wise to watch coolant temps with a scanner wjhile sorting this out, no need to go to 245 while testing,
You can buy one from Rovers North or Atlantic British, or a dealer. If the cooling system has stop leak running in it, it can stop up small metering holes in the top of the stat that allow hot water to enter, operate the stat, and make it open. It depends on flow through the bypass circuit. Heater core could also be plugged up contributing to this, you should test heater core for flow in/out, or just bypass it by a length of hose to take it out of the circuit.
Cold from bottom radiator hose in the bottom, when open that moves out the "arm" to the water pump. The hot coolant sample moves down the top axial opening. Normal for top two hoses to be warm as coolant flow at metering rate is always underway. IMHO, the dang metering holes are too few in number, but that is just my opinion.
Flow chart attached.
There have been posts of brand new ones failing to open. One DIY used hot water from a tea pot to test his.
The spec for a factory stat is start to open at 180F, full open at 204F. It is an inverted bypass stat, that plate with the holes in the top can move down by pressure when the main stat is not open when engine is revved up. So the idea of tripple checking the water pump rotation direction is a good one. It is reverse direction, facing the engine, it should turn counter clockwise.
You are wise to watch coolant temps with a scanner wjhile sorting this out, no need to go to 245 while testing,
Thanks Savannah Buzz:
The cooling system only has Motul Inugel diluted to 33% (remember we have 80deg F yearlong) so no "Stop Leak" here.
Thanks for the diagram, we checked the first tstat and figure how it works, the pump is constantly circulating coolant through the tstat until it opens and then sucks coolant from the radiator.
The heater works fine, and the water pump can only rotate in one direction(counter-clockwise) as the serpentine (if installed properly) does not allow it to rotate clockwise.
Here's how most of the heater cores are done in PR - submitted by our man slanginsanjuan. Of course, it "disco-nnects" the built in "water fall sound" alarm for leaky head gaskets...
D2 Thermostat not opening
