Going to be changing the AC compressor on my 98 LS400 in the next few days and want to see if anyone knows if it can be done without needing to drain and remove the entire coolant system, the one write up I found goes through draining the engine oil as well as the coolant etc.

Was hoping it might not need to come to that.

Thanks

 

You must evacuate system before removing compressor, otherwise the Freon is released into the atmosphere.

Oftentimes an aftermarket supplier will.require proof that your new A.C. compressor was installed and charged by a certified mechanic should a warranty issue arise.

If your A.C. compressor clutch is the only issue, then consider replacing the clutch bearing.

See;

https://www.clublexus.com/forums/ls-1st-and-2nd-gen-1990-2000/864442-ac-compressor-clutch-p-n.html

 

I bought a used ac compressor off of Ebay so there is no proof needed etc, I know I need to vent the pressure lines but in terms of physically installing the new ac compressor can it be done without removing the cooling system and draining the radiator etc.

 

Not sure why it would be necessary to drain radiator or cooling system (Engine)

By asking the question suggests you are unsure how the AC system works.

So...NO...

This is not a do it yourself proposition.

There is another item you must replace along with the compressor.

Peruse forum postings for those answers.

Consult with a climate control technician.

 

I've built 15 cars from the ground up so I'm very comfortable with working on cars. Here is the post that states the coolant system needs to drained. Thank you for your opinion.

https://www.lextreme.com/how-to-repl...er-compressor/

 

I have a '91 and have never needed to deal with the compressor. But I've done a lot of other stuff on this car, and know that the service manual (that you cited there) does often tell you to do extra steps. I'd say it's definitely worth a try to see if you can do it without draining the coolant and removing the radiator. Looks like they're just saying to do that to get room.

But if you do drain and remove the radiator, I'll say it's really easy to drain the coolant enough to disconnect radiator hoses. Not like a full coolant flush. Just open the radiator drain, catch the coolant in a clean pan, and depending on how clean and new it is, you may just re-use it. Radiator removal is pretty easy too. Surely you'll figure things out as you go.

Good luck.

 

Totally agree with this. Step 2 is remove hood. You gotta be kidding me. Why would ya do that? Whenever I need something done I read my manual and then check the forum to see what doesn't need to be done. Removing radiator is just for space. Hell, I left the radiator in on all my timing belt jobs, it's not "actually" in the way. You can drain the coolant a little if you need to remove the upper radiator hose but no need to drain the oil.

 

Here's an unrelated data point on the accuracy (about steps being really necessary) of the service manual from a post of mine related to replacing the front lower control arms:

https://www.clublexus.com/forums/ls-...ml#post9819966

Basically the service manual tells you to remove the entire front suspension. Reality is that with some skill and effort, you can literally replace the lower control arms without removing anything else at all other than obviously the bolts holding it in. And that is not atypical.


And looking again at the service manual link you provided, as Deanshark said, that is crazy. Remove hood ?!?!?! And remove engine undercover is probably necessary if you remove the radiator, but if you don't really need to remove the radiator ...

So as said, just remove "whatever it takes."

 

I noticed the same thing when replacing the alternator. The manual states something like removing 1/2 the rhs of the engine bay (well, almost).
With some care, I was able to remove Just the alternator out the bottom with just the engine undercover removed. I'm not saying it was easy, but I was able to do it.
Come to think of it, I think I did have to slacken something, but not anything that disturbed a seal. Power steering lines if I remember correctly. Job took me a fraction of the time they said it would.
Any my car (98 Celsior - LS400) still has no leaks of any kind, so I didnt push things around to the point of unsealing anything.