A/C low pressure valve

Where is the A/C low pressure valve located on a 98 grand prix gt 3800???

Where is the A/C low pressure valve located on a 98 grand prix gt 3800???

Welcome to AF.

It is located right next to the accumulator on the low pressure line feeding the accumulator on the driver's side of the car. Plus you will see the sole wiring harness going to it.

BTW - It is a low & high pressure switch combined.

Welcome to AF.

It is located right next to the accumulator on the high pressure line feeding the accumulator on the driver's side of the car. Plus you will see the sole wiring harness going to it.

BTW - It is a low & high pressure switch combined.

Is it connected onto the firewall? or is the one near the airbox on the drivers side? if its the one attatched to the firewall then my gueage is the right guage an therefore my next question.

So if i wanted to charge my freon which i do. I have the the freon and a interdynamics guage and hose line that hooks right on to it. it shows around 170 on the guage saying warning. how can i fgill my ac with freon? there is way to much pressure pushing out to put anything in. what do i do?

So if i wanted to charge my freon which i do. I have the the freon and a interdynamics guage and hose line that hooks right on to it. it shows around 170 on the guage saying warning. how can i fgill my ac with freon? there is way to much pressure pushing out to put anything in. what do i do?
By the nature of your question you really need an ac pro to do this for you, also the system is charged from the low side access port not a pressure switch fitting, I would advice stopping now! Plus where did the freon go? The low side port is under the air box.

By the nature of your question you really need an ac pro to do this for you, also the system is charged from the low side access port not a pressure switch fitting, I would advice stopping now!

I don't think i need an A/C pro to charge freon into a car. just what tools are required. I spent 8 years as a f-16 mechanic. so if i was going to blow myself up i would have done it by now :)

Is it connected onto the firewall? or is the one near the airbox on the drivers side? if its the one attatched to the firewall then my gueage is the right guage an therefore my next question.

So if i wanted to charge my freon which i do. I have the the freon and a interdynamics guage and hose line that hooks right on to it. it shows around 170 on the guage saying warning. how can i fgill my ac with freon? there is way to much pressure pushing out to put anything in. what do i do?

The low port to recharge is firewall only!!!! 170 is too high and probably the high side port. Low port has the smaller valve.

It can be done DIY but if you have no experience leave it up to a Pro A/C person.

I don't think i need an A/C pro to charge freon into a car. just what tools are required. I spent 8 years as a f-16 mechanic. so if i was going to blow myself up i would have done it by now :)

Thanks for the service to your country.

Shep if he can work on an F16 he can DIY his car.

BTW - My son is in the Air Force stationed at Osan AFB. He is a GEF110 jet engine tech.

Good luck!

The low port to recharge is firewall only!!!! 170 is too high and probably the high side port. Low port has the smaller valve.

It can be done DIY but if you have no experience leave it up to a Pro A/C person.

The only A/C port i'm finding is the one on the firewall which i had already assumed is the high side because of the pressure reading. Is the low side somewhere beneath the vehicle? out of site where i would need a jack?

Thanks for the service to your country.

Shep if he can work on an F16 he can DIY his car.

BTW - My son is in the Air Force stationed at Osan AFB. He is a GEF110 jet engine tech.

Good luck!

Most of my good friends are either at kinsan or osan right now. I just got out and stayed in las vegas.

Ok so here is my question. I've found the high side which is on the firewall? where is the low side. someone said that the high side is also the low side. so will i need a special connector? or is there another port to input the freon? What i need to know is where to put the freakin hose an pull the lever cause its really freaking hot in vegas an i have no A/C and no tint and its like 108 outside right now!!!!

O an im at work in a suit. I really want to charge this A/C haha. its hot... really really hot. and i dont want to use mac trucks to shadde my drive home anymore.

Ok so here is my question. I've found the high side which is on the firewall? where is the low side. someone said that the high side is also the low side. so will i need a special connector? or is there another port to input the freon? What i need to know is where to put the freakin hose an pull the lever cause its really freaking hot in vegas an i have no A/C and no tint and its like 108 outside right now!!!!

No, the low side is the one at the firewall on a Grand Prix. The high port is by the accumulator which is that big cylindrical looking part which is similar to a receiver drier unit in other GM cars.

You put the R134a refrigerant into low side port only. It has the smaller valve/fitting.

If you are immediately getting a high reading on the low side port and your testing equipment is not at fault then it could be a bad orifice valve or worse case a compressor. When low side pressure matches or is within 30 psi of high pressure then those are the possibilities.

BTW - My son is with the Dragon Lady. Thats all I can say or they will kill me....lol. :lol:

By the nature of your question you really need an ac pro to do this for you, also the system is charged from the low side access port not a pressure switch fitting, I would advice stopping now!

well i overlooked your anwser thanks. It seemed to have trickeld out over the winter. i'm sure i have a leak somewhere but i want to see how bad it is.

No, the low side is the one at the firewall on a Grand Prix. The high port is by the accumulator which is that big cylindrical looking part which is similar to a receiver drier unit in other GM cars.

You put the R134a refrigerant into low side port only. It has the smaller valve/fitting.

If you are immediately getting a high reading on the low side port and you testing equipment is not at fault then it could be a bad orifice valve or worse case a compressor. When low side pressure matches or is within 30 psi of high pressure then those are the possibilities.

BTW - My son is with the Dragon Lady. Thats all I can say or they will kill me....lol. :lol: hahahaha....

Ya'll i need to know exactly which one it is the one i found attatched to the firewall that sticks out and my guage attatches to is showing 170 psi which is not good. If that is not the low side then i will remove the air box but there is another chromje tube next to the airbox but the valve is different like a ball bearing. holding pressure to keep the ball in palce of the hole. a little different then the bicycle tire style valve that the one on the firewall has. plus my guage and hoseline won't fit that valve.

hahahaha....

Ya'll i need to know exactly which one it is the one i found attatched to the firewall that sticks out and my guage attatches to is showing 170 psi which is not good. If that is not the low side then i will remove the air box but there is another chromje tube next to the airbox but the valve is different like a ball bearing. holding pressure to keep the ball in palce of the hole. a little different then the bicycle tire style valve that the one on the firewall has. plus my guage and hoseline won't fit that valve.

That is correct on the high side port by the airbox. You need the bigger adapter and the special gauge to read high side pressure. I have the figures from the GP GM service manual for both low and high readings so let me know if you need them. But right now you have a problem if the low pressure is reading that high. It should read around 30 - 60 psi or so depending on the ambient temperature if properly charged.

Ok so the one attatched to the firewall is the low side. when i took the cap off green freon was oozing out of it. hehe. umm yea its showing at 170. should i let the car sit should i have it running should i rev the engine should i turn on the a/c these are questions that i need aswesered. i would very greatly appreciate it. thank you in advance.

Ok so the one attatched to the firewall is the low side. when i took the cap off green freon was oozing out of it. hehe. umm yea its showing at 170. should i let the car sit should i have it running should i rev the engine should i turn on the a/c these are questions that i need aswesered. i would very greatly appreciate it. thank you in advance.

To properly check low side pressure, car should be idling, the A/C should be on full blast...max and high fan speed. Then see what the reading is.

Yea i don't think its the freon. i think something is really screwed somewhere else. last year i broke a belt and it tore the water pump. i had that replaced. i wonder if there was some damage somewhere else.

its now sitting at 70 PSI

its now sitting at 70 PSI

70 psi is a little on the high side but it depends on your actual air temperature where you live. High low side pressure can be as bad as an undercharge.

What exactly are your symptoms as far as A/C?

There is 0 cold air the a/c and everything seems to kick on you can feel it draw power from the engine. i know that the A/C worked last summer. but as soon as i tried to use it when it started to get a bit to warm here in vegas there is nothing it runs and degrades engine performance but no cold air.

I would really hate to drop it at a shop so they can try an stick it in my behind with a bill. then i gotta go over each part with them. i don
't have a mechanic that i can trust out here so i'll have to hunt someone down.

That is correct on the high side port by the airbox. You need the bigger adapter and the special gauge to read high side pressure. I have the figures from the GP GM service manual for both low and high readings so let me know if you need them. But right now you have a problem if the low pressure is reading that high. It should read around 30 - 60 psi or so depending on the ambient temperature if properly charged.
Guys, sorry if I offended anybody with the need for a pro comment, but a/c work can be tricky without the proper tools and backround. The system should really be evacuated and drawn down to see if it hold vacuum, then an initial charge can be put in as the vacuum makes it easier to get that first can in, if it held vacuum for 1/2 hour there usually are no leaks, anyway on my 98 W body 3800 Lumina, the low side is under the air box and so is the high side port, the GP is configured different?

Guys, sorry if I offended anybody with the need for a pro comment, but a/c work can be tricky without the proper tools and backround. The system should really be evacuated and drawn down to see if it hold vacuum, then an initial charge can be put in as the vacuum makes it easier to get that first can in, if it held vacuum for 1/2 hour there usually are no leaks, anyway on my 98 W body 3800 Lumina, the low side is under the air box and so is the high side port, the GP is configured different?


I don't see any problems Shep. It doesn't hurt to help him out DIY if he wants to do it that way. If DIY fails he can always take it to a Pro but at least he gave it shot. Also, you have to realize your Lumina is a Chevy. The layout on alot of things are different even between similar GM 'W" body classifications.

He needs to check high side pressure with the proper gauge and fitting and run a comparison versus low side pressure to see if both readings are in range. Although the compressor sounds like it is cycling it could be flaky (destroked) or maybe the orifice valve.

For now I agree the best thing to do is have the system evacuated, tested and then recharged.

I don't see any problems Shep. It doesn't hurt to help him out DIY if he wants to do it that way. If DIY fails he can always take it to a Pro but at least he gave it shot. Also, you have to realize your Lumina is a Chevy. The layout on alot of things are different even between similar GM 'W" body classifications.

He needs to check high side pressure with the proper gauge and fitting and run a comparison versus low side pressure to see if both readings are in range. Although the compressor sounds like it is cycling it could be flaky (destroked) or maybe the orifice valve.

For now I agree the best thing to do is have the system evacuated, tested and then recharged.
Agreed, Max

Killiah, Bnaylor and Max have you covered and I agree with them. Comparing the low and high side readings is the first thing you have to do.

Mike, many of those DIY kits have leak detector and sealer in the Freon cans they come with, so they might fix your issue if it's a small leak.

How about we limit responses to Mike561 to this thread only:

http://www.automotiveforums.com/vbulletin/showthread.php?t=587873

Otherwise, there will be redundant posts and things will get confusing.

Forum rules do not allow multiple posting and running separate tracks on the same issue.

sorry bout that, the other ac issue came up after i posted in here, i deleted mine from this thread.