V70 Trans DIY Cooler Upgrade - OEMish

[Botbasher]

Morning Everyone!

I was able to get one of my big ticket projects checked off the list this weekend and thought I'd share it with you so that those in need or similar situation might benefit. It was really simple and required no special tools. This may work for other models, but I have not compared them... I can only speak to the P2 V70s.

Parts and unique tools required:

• 1999 Volvo C70 Transmission oil cooler 8618347 (other years may also work)

• 3/8" Hot Oil Rated Hose - about 3 ft

• Transmission Cooling Hose Retainer 9485149 - 1

• Transmission Cooling Hose O-Ring 988840 - 2

• 3/4" Hose Clamps - 6

• OPTIONAL but HIGHLY RECOMMENDED - Magnefine 3/8" Transmission Filter

• 7/8 Open End Wrenches - 2 (preferably thin type)

• Dremel or Angle Grinder with Cut Off Wheel

• 1"x6"x12ga Stainless Strip (any strip will do in a pinch, but this will get abused and rust!)

• 3/4" 1/4-28 Stainless hardware set (Bolt, 2 washers and Nylok Nut (or split washer and regular nut)

• Various Hand Tools to work with hoses, clamps and removing the Swage Fittings on the hoses

• Drill with 1/8" and 3/8" bit for removing aluminum rivets and drilling SS Strip

• OPTIONAL - Hose Cutter for nice clean hose cuts

For those following my adventures with Sven here you know that I have been having some shifting issues I attributed to heat building up in the trans. I believe that I either have a VB shuttle or bore that binds or leaks when the trans gets warm. I see the issue after something like a drive through or in cue to pick up after school. After a bit of air passing over the radiator, the shifts would be buttery smooth again, until the next stop & go session. I had to find a fix!

I have tried all the basic stuff, from Fluid Changes to Adaptation Runs. I rebuilt the Linear Solenoids yet nothing seemed to work to completely eliminate the harsh shifts after a bit of heat. Heat was the basis for the issue, so what is the best way to remove the heat? An Aux Cooler, right? Now getting an Aux Tran Cooler is no biggie, right? $80 online and you got it, but you'll have to mount it and then figure out how to plumb it into the system. I took a little more OEM approach.

While searching for Trans Coolers on-line, I happened across Roberts (RSPI on the Forum) DIY for this cooler on a P80 platform. Hmmmmm It's Volvo. It's going to fit OEM or damn close. The fittings are all there making plumbing a snap. Yeah... SOLD!!! Once it got to me in the mail I cleaned it out thoroughly (no sense in putting someone else's gunk into my trans!!) and started planning!!

Now removing the front bumper is well documented in other DIYs and I will not rework the same DIYs that I used, so do a quick search on "P2 Front Bumper Removal" and you'll be done in no time. It took me longer to jack up the car than to remove the bumper!

So once you have the car in the air and safe to work under... Get ready to install your "new" Trans Cooler!!

2002 S60 Trans Cooler

Now I am not sure about all, but mine and my buddies 06 V70R both have what appear to be mounts for a similar set-up which is where I got the idea from. The V70 is a bit wider than the S60, so a bit of adaptation will be required, but I'll show you what I did and in less than an hour I had it ready to roll again!

I took the portion of the mounts that would, in a non-turbo car, attach to the radiator mounts and removed them. They are not deep enough and simply won't fit in this application. We're not talking a ton of weight and it's on some serious mounts, so I have no issues with it. You make that call for yourself. Drill out the rivets for the unneeded mounting points. Don't toss them too far yet as they come in handy in a few minutes!!

Drill out the existing rivets and discard the mount.

Take the Drivers Side tab on the cooler and on the radiator and loosely thread the bolt through it. I put the bolt into the Radiator side, so it was much easier to thread and tighten. There is not much room to swing in there! Do not tighten all the way down as you have a lot of manipulation yet to cover. If your car is REALLY high off the ground, a zip tie between the other mounting hose will keep it safe from twisting and damaging the fins.

Drivers side mounting tab

Passenger side mounting tab

Once you have it loosely in place, line up the passenger side with your 1" strip and mark where you will need to drill your holes to make an adapter to stretch between the Rad Mount and the Cooler Mount. You might need an additional set of hands, or amazingly enough, take the old riveted mounts, hold the rivets together and mark the distance between those holes on your strip. They make it exactly the correct length! Volvo... gotta love em!! If you mark it correctly, the edge of your strip fits nicely into a lip on the rad support. This will keep the bracket from drooping. If you want to double down on support, put a second strip on top on that butts up to the cooler the same way, but on the other end will keep it level. Jury is still out on this, but I may weld a little tab on there if I see it sinking! There is plenty of room between the bolt head and the Condenser, so just put the bolt in that way and you are fine!

The mount for the pass side

The mounted cooler

Drivers side with hoses pointed right at the trans!

Now that you have the cooler on the supports, tighten down lightly until you are sure it's all aligned properly and then cinch it down. Because Volvo intended it to be used like this, the hoses are now positioned for easy manipulation on the drivers side, right in front of the trans and right below the existing cooler!! Too easy, huh?


Now take a quick potty break... grab a cold drink and get ready for the fun parts!!!

Continued in next post!

Cheers!

K "verbose" S

[Botbasher]

OK, so in our last episode, we had a mounted trans oil cooler and we were about to start having fun!!! Let's get to it!!!

Now you have a couple of choices to make. I decided to simply augment the existing cooler in the car. It's easier and if I really want to I can rework the hoses in the future. For the moment, we are going to just add this cooler to the car. So start by removing the existing return line from the trans side of the system. Undo the upper side of the return first and blow into it to empty the line. If you don't, there is always a little ATF sitting in the loop and it gets everywhere... ask me how I know!!

Looking at the trans return line on the driver side of the car.

Now grab a pair of 7/8th wrenches. A thin one is required!! Remove the existing return from the car watching for spillage as you rotate the hose to extract it.

Use a back-up wrench or you risk stripping out the hole!!

So here is where some decisions for different directions can be made depending on car and DIYers situation. I was going to use the S60 return hose as-is... and it actually fits, but it was a bit tight for my liking on factory mounts. Maybe if I had polly mounts or no intercooler or evaporator, but it vibrates and I don't feel like pouring out my ATF on the street when I snap the hose! It interfered with the intake just a little bit. So I decided to repurpose the existing return line after a little modification.

Look at the existing hoses and accessories in the intake area and determine the best location to place the Magnefine Filter is you decided to put one in. Cut the upper end of the return line and install a clamp and the filter. Make sure there is nothing in the way that moves (like the gear selector!!). Check twice, cut once!!! Feed the hose down through the opening and reinstall the return line with new o-rings and clip if needed.

About 4-5" down the line seems like a nice out of the way place!!

Make sure it won't catch anything!

Once you have it reinstalled on top, come down below and install the hose on to the lower fitting. I put a little ATF on the barb and slipped it right on. I used GATES hoses which can be super stiff and hard to manipulate. Just take your time and make sure that you have a good clamp and a half over the barb before you stop!


OK... last bit before you are done.....

[Botbasher]

Now because I decided to reuse the existing V70 return line, I had to remove the old hose from the fitting. Take a Dremel or angle grinder and while wearing safety glasses and gloves (safety first, right!), carefully slice the swage off the hose. DO NOT COMPLETELY CUT IT OFF!!!! Only cut down deep enough to make it easy to tear apart. If you cut full depth, you will nick the pipe and damage the barbs! Use a strong screwdriver to wedge and pry. The connectors are easily snapped and it will part!

Don't cut all the way through!!

Done!

Once you have it off, attach the 3/8th hose and reinstall it on the trans pan. I reused the existing hose protector from the S60 hose as an added benefit!

Use two wrenches to reinstall it!!!!

Now size the hose to the other fitting on the cooler and cut hose to length. Remember that this part WILL MOVE independently of the cooler, so leave enough slack to compensate for it!! Again, push the hose onto the fitting stopping only after you have at least one and a half clamp lengths over the barb. Collect both hoses and make sure they are routed properly.

Lots of slack without having extra!

You are done with the install!!! Now you need to add ATF for any you lost in the disassembly and for the new volume of the cooler. I added 700ml as a 1st guess. I put the car back on the ground, started it and found it was just about 200ml low cold. I let it idle and warm up while I checked for leaks. I found none and reinstalled the bumper which is amazingly simple IMHO!!!

A short drive to warm up the ATF and a quick recheck showed it about 100ml low. I added the missing ATF and closed it up!

So now I have a mostly OEM Trans Cooler. It wasn't quite a bolt on, but there was nothing that needed extensive fabrication. Heat is the sworn enemy of a automatic trans, so anything we can do to cool it down will help. I am looking forward to seeing how it effects the issues I have with my 03!

Hopefully this helps some with similar issues or those that want to push the cars and need some extra capacity!

Cheers!

K "Cool!" S

[matthew1]

KS, very nice. Great writeup too. I moved your account up to MVS Contributor. I'll put this in the VRD.

Let me know if you want the Contributor avatar, leave it alone, or a mashup.

[Botbasher]

KS, very nice. Great writeup too. I moved your account up to MVS Contributor. I'll put this in the VRD.

Let me know if you want the Contributor avatar, leave it alone, or a mashup.

Thanks Matt!!

Nice to give a little back for all that MVS has given!! With so much here is hard to find something new to cover!!

Door #3 sounds exciting Monte!!!

Cheers!!

K 'DIYin it' S

[Botbasher]

Hey Matt... or any available Mod... Since I can't edit this and found a GLARRING ERROR... could you edit this into the parts list for me??

The actual part required is a 1999 Volvo C70 ATF Transmission oil cooler 8618347 #1 on the list.

I guess I read my notes incorrectly and it totally slipped till I was talking to another V-Nut this weekend and he caught it.

Sorry for any confusion and difficulties! The rest stands correct!

Cheers!

K "needs glasses" S

[matthew1]

KS, please try now. I temporarily paused the 6400 minute editing window that normally applies.

[Botbasher]

KS, please try now. I temporarily paused the 6400 minute editing window that normally applies.

Done!!! Thanks for letting me fix my boo boo!!! Glasses are on order!

KS

[precopster]

Just to clarify: did 1999 C70s come with a separate transmission cooler while garden variety V70s and S70s had the cooler built into the radiator?

I always thought all models had coolers in the radiator.

[Botbasher]

Just to clarify: did 1999 C70s come with a separate transmission cooler while garden variety V70s and S70s had the cooler built into the radiator?

I always thought all models had coolers in the radiator.

Pre...

I have to presume this was some kind of upgrade or special (towing?) package as it had fittings that went between the radiator and transmission return. I couldn't use it as-is due to the flow differences between P80s and P2s... But it was definitely used in conjunction with the radiator's ports.

Looking online I found it and similar used in several places. I would think towing, ambulance and police if I pressed for an obvious use.

I'm thinking about adding one to my 98!!! No issues, but it wouldn't hurt!!

Cheers!

K "guessing" S