Land Cruiser 100 expansion valve caused havoc on vehicle and fuel economy

[MJB]

I thought I would share my experience with this issue if it would help someone else with the same symptoms on their 100 series.
My 2004 100 series 4.2 1HD-FTE blew a High pressure pipe last year and since then it was the one issue after the other on this ac system. The compressor pully went next after I replaced the high pressure pipe it shattered itself. Then the condenser blew after replacing the pump, I thought maybe to replace the high pressure switch as it was clearly not doing its job of protecting the system. Mind you when the AC was working it was working very well.
So after all this I noticed after fixing and replacing everything that my vehicle was also quite heavy on diesel it would give me 5km/L in town and 6km/L on highway also noticed that it was lacking power. Someone suggested my turbo was seizing up so checked it and its perfectly fine. Come to find out after alot of research that my AC expansion valve in the dash was stuck open causing the AC pump to work permanently basically. Replaced it with an amazon A-Premium one and you cannot belive the difference in power and fuel efficiency Im still stunned that this small part was causing all this issues on my car. So for anyone have similar issues don’t overlook that dam expansion valve.

 

[gregdawg89]

Hi, where exactly is that valve located in the dash? Do you have pics? What is the part number in case we need to order one? Thanks!

 

[MJB]

Hi, where exactly is that valve located in the dash? Do you have pics? What is the part number in case we need to order one? Thanks!

Hi Greg, it is located on the evaporator in the ac system behind the dash. You have to remove the glove box and a few plastic covers there are alot of youtube videos on how to remove the evaporator and the expansion valve bolts to the evaporator. The part nr for the front expansion valve for the 100 series with Front, Rear AC & cooler box system is 8851560120

 

[MJB]

I done my first road trip with the vehicle today after all the repairs and replacements on the ac system and the fuel consumption has gone up from 6-7km/L to 10km/L with high way driving. Quite an improvement

 

[StarCruiser]

Are you sure the TEV was stuck open? Usually with pressure issues it is plugged shut. This can happen if moisture is allowed to enter the AC system and not removed after a careless recharge or a leak. The moisture instantly freezes at the TEV (thermostatic expansion valve) and plugs it solid causing back pressure like you’ve experienced particularly if the system is overcharged.

Applying a vacuum pump to the system emptied of refrigerant on both high and low side can remove moisture but should be left on over night to boil it off.

 

[MJB]

Are you sure the TEV was stuck open? Usually with pressure issues it is plugged shut. This can happen if moisture is allowed to enter the AC system and not removed after a careless recharge or a leak. The moisture instantly freezes at the TEV (thermostatic expansion valve) and plugs it solid causing back pressure like you’ve experienced particularly if the system is overcharged.

Applying a vacuum pump to the system emptied of refrigerant on both high and low side can remove moisture but should be left on over night to boil it off.

Yes it was stuck open partially and did not close or open fully so the AC was still working as normal but the pressure was always running high and the pump was not cycling on and off as it should which lead to a lot of stress on the pump and engine. I have my own fully automatic AC recharge machine at my shop so the system was always fully vacuumed after being open to remove moisture so don't believe that would have caused an issue. I fiddled with the expansion valve I removed and you could see its stuck open, also blew through it with compressed air to test it had some resistance but air was going through. Also did the heat and cold test on the thermal bulb and it did nothing did not even click like it should. There was also no debris inside it so I believe it was just tired after 20 years. But after replacing it and driving the vehicle it's a big difference in power and fuel economy and the AC is working ice cold. The rear AC and Coolbox are all also working well so believe my Cruiser is sorted for now until the next thing goes...

 

[Dave]

A stuck open TXV won’t cause high pressure, in fact the opposite, and the compressor won’t have to work harder as its not pumping against anything.

 

[MJB]

A stuck open TXV won’t cause high pressure, in fact the opposite, and the compressor won’t have to work harder as its not

Dave the thing was malfunctioning I replaced it the car is better I am not an AC specialist but replacing the TXV valve resloved alot of issues on my car including the extremly heavy fuel consumption I was having so I am happy and just want to share the experience for anyone whom may have similar issues

 

[Grimbo]

Running AG machines on a dyno we typically see A/C compressors take between 5 and 8hp on older tractors and still 4 hp + on the latest spec systems .
Most machines now run vistronic cooling fans that are pretty much infinitely variable and controlled by A/C , engine and transmission ECU's according to requirements so the fan will constantly ramp up and down speed . A big fully locked cooling fan can be drawing up to 25hp from the engine..... so you can see why your fuel consumption may well have been affected

 

[StarCruiser]

Most interesting info here. Well done finding the TEV as the problem and clearly a thorough check of the replaced part aside from it curing the problem showed it to be faulty. Interesting on the fan hp draw.