Forum:
I have a 2.8 td engine in my Landie and added a VDO temp. guage to keep an eye on things. It runs around 170 to 180 degrees(F) around town and about 187 to 190 at highway speeds or up to 200 on long highway grades. What does the same engine run at in a Fourtrak? Do my temps seem normal?
Hot Under The Collar
Fourtrak's run at various temperatures, this is due to certain factors:
Thermostats come in differing temperatures, these are generally due to winter and summer temperatures in the uk, basically these allow an engine to warm quicker in winter, and slower in summer. Check the temperature stamped on the stat, or the manufacturers data to see what temperature rating your stat is running.
Many parts are sourced by importers from differing regions of the world, the temperatures of the stats will be compatible with the temperature of that country, maybe a lot hotter than the UK, maybe they are from a cooler region of the world.
I suspect you have another problem, you say you have a VDO gauge, these are generally aftermarket fitments; often these are connected directly to the engines original temperature sensor, this may not be compatible with your gauge. Temperature sensors work on resistance, the hotter the engine temperature the lower the resistance reading on the temperature sender, my suggestion would be to get an original and compatible VDO temperature sender. Another option is to mount the internals of a Fourtrak temperature gauge into the VDO housing.
It is apparently obvious that at these temperatures, the engine should be overheating and spewing water and steam out everywhere, and it is not, this is a common problem i have seen too often in the past.
Why would you assume I did
Why would you assume I did not use a proper VDO sender? I did. 180 to 200 is not overheating in any engine, it would not boil over even with straight water rather than the 50/50 mix I am using at those temps. The engine is equipped with the ACSD so should have the thermostat that starts to open at 185 or so and is fully open at 210. I am not saying it is overheating, just wondering what others experience to compare it to the original fitment. My radiator has 30% more capacity than the daihatsu OE so cooling should be more than adequate.
Based on many years of
Based on many years of experience of seeing these problems, most people transplanting engines use the original engine sensor, rather than a compatible sensor, as you have, you are in a VERY small minority.
Radiator capacity is irrelevant, it is a common misconception that most people have, the relevant factors are how efficient the radiator is at converting heat, most racing engines and cooling systems i have built over the years often have a smaller radiator fitted, and need to dissipate more heat, therefore they are considerably more efficient.
A phenomenan occurs, which is far to in depth to go into on a forum such as this, which causes localised heating of the cylinder head, the upshot is heating of the cylinder head which causes it to steam, this ends up coming out of the radiator and gives the appearance of overheating.
Anti-freeze actually lowers the boiling point of water, this is why the system is pressurised, this pressure increases the boiling point of water. Daihatsu radiators are actually very efficient for their day, where as Land Rover radiators were not, this is where more problems have occured in the past with transplanted engines.
Ethylene glycol
"Anti-freeze actually lowers the boiling point of water" - my understanding is that Ethylene glycol RAISES the boiling point of water....
1985 Veg oil burning Fourtrak "Rocky".
Ethylene glycol
Ethylene glycol mixed with water elevates the boiling point and depresses the freezing point. Pressurising the system also raises the boiling point which is the principle that pressure cookers and autoclaves work on. Oddly enough, pure ethylene glycol freezes at -13 degrees C, but a 50:50 mix with water freezes at -60 ish degrees C. Elevation of boiling point by the addition of a solute happens because the molecules of the solute interfere with the way in which the water molecules break from the liquid phase and become gaseous. The depression of freezing point is similarly caused by the solute molecules preventing the formation of the bonds which hold the water molecules together in crystals when water freezes.
Anyway, this is all off topic, 100 degrees C is 212 degrees F (we in the UK are probably more comfortable with Celsius than Farenheit). Most thermostatic fan switches switch on at 87 C and off at 82 C. I would therefore expect the coolant temperature to be maintained within this range.
When I replaced the broken temp gauge in my truck with an identical one from a spare vehicle, it went off the scale while the head was still cool enough to touch. I ended up buying a new after market gauge and sender to suit and it worked perfectly then. I let the engine warm up from stone cold with a temperature probe stuck in the top of the rad just to confirm the temperature and to be on the safe side. When the thermostat opens you get a rush of hot water into the rad and you can read its temperature. Let it idle for 15 mins and keep an eye on the scale. Mine didn't budge from the low 80s C.
Make sure the connections to the sender are clean and not corroded, cut them off and solder or crimp new ones on if in doubt, a little bit of oxidation of the copper can interfere with the resistance and give bogus readings. One other thought - on my 2.8 TD there are two senders in the head, one is for the gauge, the other is for the glow plug timer which I have junked. Are you using the correct one?
Regards - Alastair.