I start up my 98 Dakota 5.2l and usualy have cold ac for 15 to 20 minutes then it gets warm. I can turn off the ac for 5 minutes and then it will blow cold agian for a little while. Somtimes it last longer sometimes only a minute or so. I put the guage on it and it was on the line between being low and having enough so I added a little to get it in the green, didn't help. Any ideas what I should check. Maybe a switch somewhere or something?

rhutson in NC

 

first do not use refridgerant sealeer stopleak miracle additive - only use r134a.
Alway use gauges - need both high and low readings.

SO lets look at this...easy simple first
>Is the CEL on?
>Is the evaporator drain discharging water - do you hear water sounds in heater area thinking is Freezing on evaporator.
>Try selecting A/C don't use MAX...freezing idea again
>Be sure fan is operating if electric - fan clutch good if eng driven- thinking hi press cut out

answer the easy ideas then we will get checking hi and low switches -will need DVOM or test light and gauges high and low.