AC Help

So I have an 03 DC. While running down the road my AC works alright at best. Sitting at idle on a hot day is a different story. The AC compressor clutch is engaging and working. I bought one of the self charge cans and hooked up the low side with the clutch egaged and got a reading on the high side. I revd up the engine a little and the reading dropped really low. I did not add any refrigerant because this seemed odd to me. Is that normal?

 

Without having gauges on the high and low side of the system it's not possible to really diagnose and A/C system effectively, a number of things could cause high low side pressure and poor performance at idle but you need manifold gauges to see the whole picture. If your not sure what to look for on pressures vs ambient temp it's probably best to take it to someone that knows A/C systems.
A couple things you could check on your own are make sure the radiator and condenser aren't plugged with dirt or trash and make sure the cooling fan clutch is working (if it's barely spinning at idle and/or keeps turning for more than about a second after the engine is turned off it's bad).

 

check the AC belt for its condition and tension. I have a 1st gen tacoma with a 3RZ that had similar symptoms like this and i tighten the belt up some and that fixed the issue. Im not saying this is the problem but it dosent hurt to give this a try. Its free and easy to do before doing anything else. Good luck

 

Get some of that spray foaming coil cleaner your not getting enough heat transfer .

Always spray the water from the truck side.

 

Look up ChrisFix’s YouTube video to learn how to use manifold gauges if you try working on it yourself. Using those single gauge cans can overcharge your system when you don’t know the pressure on both sides. But it is normal for the low side pressure do drop when the compressor engages, it’s sucking it up to compress on the high side, it’s how it works. But when properly charged, that fluctuation shouldn’t be very large. Also, it won’t work as well on real hot days when at idle bc there’s little to no air moving across the condenser fins to dissipate the heat.

Anyhoo, you can get a set of manifold gauges from harbor freight or Amazon. Just make sure you know how to use them before wingin it or you could make some dangerous mistakes, ask me how I know.

 

Older thread I know, but can you explain this a bit further? I’m having a similar problem and would like to try your solution. Coils? Spray water from truck side? Thanks!

 

Putting your manifold gauges on and seeing what pressures you have should always be the first step.

This will not fix electrical problems just transfer of heat problems

In AC work the physical parts of the condenser and evaporator are called coils .\

In buildings some can be huge .

The condenser on the front of the truck tends to get filled with bugs and other assorted road dirt not allowing enough air flow which means reduced heat transfer.

There are spray on products made just to clean these parts industrial suppliers perhaps auto parts stores should sell them.

After 20 years the Evaporator can also get quite dirty as well

Always flush the radiator and condenser toward the front of the vehicle no need to drive the dirt in deeper.

Good Luck!

 

Thank you!

 

Your welcome !

A message would also have worked.