Melted Thermostat Housing Bung or Blown Head Gasket ?

Hi Spud Boy

I live in Littlehampton
Work at UniSA in the City
Wife works in Woodside and takes the Disco with her, so we found a Diesel mechanic in Woodside but I am not sure of their knowledge about LandRovers

Merlin

I imagine that it is pretty standard for a Diesel

However I was in a cross wind, towing a horse float (No Horse), with three kids watching Harry Potter on DVD, (Great distraction for the kids on long trips)

Well that's my excuse... and Iam sticking to it...!

Merlin

ok here's the pic of the Thermostat mod:

http://www.aulro.com/albums/album339/Thermostat_mod.jpg

<span style="color:blue">now im confused....


that pic looks nothing like a thermostat.....or a mod....


is that the blanking plug that is to go into the hose mentioned by kie4...?


someone please help me..... </span>8O

Hopefully kie4 will shed some light on the situation. I just posted the photo he sent me https://www.aulro.com/afvb/

hi yes that is the plug you put in the top hose

Kie4,
I have always been told that removing the thermostat stops the cooling system from working properly (although I have done it).
I though that the coolant would then flow through the radiator too fast to cool properly, or are you describing something different?

Andrew

you should only cut the center of the thermostat and put the outer ring back in as the restriction creates the pressure to wash the coolant right thru the block.

hi andrew , A thermostrat is put in the cooling system to aid rapid warm up of the engine.
most of the wear in an engine happens when the engine is cold.
as for the coolant going round the engine to fast, thats goverened by the water pump.
to answer incisor , you dont need a thermostat to create a restriction to wash coolant through the block, the water pump pumps the water round the block

Personally, I would never run any engine without an operating thermostat.

Why ?

Removing the thermostat is a band-aid solution (and IMHO, a poor one at that) for a cooling system problem.

Firstly, as has been stated, the thermostat aids in quickly warming an engine up to running tamperature.

Secondly, every engine, particularly diesels, have an optimum temperature at which it is most efficient/produces optimal power/least wear. In my experience, this is in the 90-95*C coolant temperature region (this includes racing engines !). This is the temp where all the operating clearances are optimal, and combustion is at its most efficient. Remember that power is synonymous with heat. Internal combustion engines are very inefficient. The heat of the expanding gases is what powers the piston back down the bore. Far too little of this heat is used for this. The vast majority disapears into the cooling system and out the exhaust (at least the tubocharger turbine harnesses some of this)
Too low combustion chamber temperature provides insufficient burn, leading to reduced power and unburnt fuel going out the exhaust. A diesel is a compression ignition engine. This means that very hot air ignites the fuel when it is injected int the combustion chamber. Not as hot as it should/could be leads to incomplete combustion, which equates to loss of power, increased fuel consumption, higher exhaust gas temperatures and increased wear.

Thirdly, I believe that most engines need a certain amount of restriction or back pressure, generally accorded by the thermostat for optimum coolant flow through the block/head. It was fairly common years ago to see irregular bore wear in Holden sixes after extended use without a thermostat.

If an engine is overheating, please don't take the (seemingly) quick fix option of removing the thermostat. Please take a holistic approach and look at the overall system. It may be a lack of airflow, (remember that the superheted air from the radiator has to exit the engine bay for ambient air to flow through the radiator. This often isn't properly addressed) perhaps the pump lacks sufficient volume, the heat exchanger (radiator) lacks surface area, the exhaust system may have a restriction, or it may be as simple as the type of coolant used can be optimised. (e.g. OAT coolants have a heat transfer co-efficient roughly half way between conventional ethylene glycols and pure water)

A thermostat is only a temperature regulator, nothing more, nothing less, but it is an important job, and not one that should be eliminated lightly.