TURBO INTERCOOLER VIGGEN UPGRADE

A special thanks to Helga & Dmitry Platonoff for the contribution of this material and some other materials listed on the sites faqs pages. It is Saab enthusiast like Dmitry that make it easier for the DYI guys that frequent the internet. Excellent Job!!!!

Click here to Email Dmitry Platnoff!

Saab NG900 Intercooler replacement and Viggen intercooler upgrade Tools

Intercooler upgrade on the 1996 Saab 900 Tools:

16 mm socket: bumper bolts;
10 mm socket: old intercooler bolts;
8 mm socket: headlight wiper nuts and lower shield screws;
7 mm socket: hose clamp screws;
long socket extensions;
ratchet handle;
flat screwdriver;
Torx T25 screwdriver;
hacksaw and files;
sharp knife;
measuring tools;
car jacks and stands or ramps

First Overview

Raise the front of the car and open the hood. Remove the grille by detaching two tabs on top.

Undo the Torx T25 screw on the turn signal assembly, remove the housing and unplug the wires.

Remove the headlights (three Torx T25 screws). Unplug the wires, use a flat screwdriver to release the locking tab on the harness.

Lift the covers over the nuts on the headlight wiper arms and remove the arms (8 mm socket). Detach the washer fluid hose from the bumper (there is a couple of metal tabs holding it).

Remove the plastic shields from below. Each side is held by half a dozen screws with a 8 mm hex head.

Unplug the wires from the FOGLIGHTS.

Detach the temperature sensor under the bumper. That horrible rusty thing is the license plate holder.

Remove the Torx T25 screw under the fender (one on each side).

Undo two long bumper bolts located next to the headlight wipers (16 mm socket).

Pull the bumper forward and remove it from the car. Mind the sides of the bumper cover while pulling: there are latches on each side that you need to release.

The intercooler is held by two long (and likely rusty) bolts. Use a 10 mm socket to remove those. Both hoses are attached on the driver's side, the clamps can be released through the headlight opening with either a 7 mm socket or a flat screwdriver (and a lot of rust solvent).

Remove the intercooler from the car. Detach the hoses from the delivery pipe and the turbo.

The old intercooler was a two-pass design, the new one is a cross-flow.

The upgraded intercooler core is made by Spear co and has a 3"x7" cross section with a flow area of 5.30 square inches. This is 60% more than a cross-flow Viggen intercooler has, and 4 times more than my base unit. There are also 5 times more fins for a much greater cooling capacity.

The end tanks are made by MP. You can see an extra weld spot: this was a discounted defective unit. I had to take it to an alloy welder for repair first. We've found four pinholes in the welds. The regular units should not have these problems, but it never hurts to do a pressure test. Also check for metal shavings in the end tanks: I had a lot of those.

The newer intercoolers MP sells now have additional grooves machined on the inlet pipes to help secure the hoses better. Mine didn't have that, and the pipes were unequal length, but then again, I knew what I was getting, and it's hard to complain considering the discount they offered.

The 900 models have an older lower radiator hose that gets in the way of the intercooler inlet hose. It has to be replaced by a new design (Saab part #4963872).

With the intercooler removed, you now have the access to the radiator drain plug. Use a piece of aluminum foil to form a trough gutter and drain the coolant into a clean bucket so you can reuse it later (assuming your coolant does not require replacement yet).

Here's the old hose next to the new style hose provided by MP. They supply used hoses, and unfortunately this one had a crack on the back. I've noticed it too late and had to reinstall the old hose since it was a holiday and the dealership was closed.

To not make my coolant drain a total waste of time, I cleaned the coolant expansion tank (it looks rather dirty on this picture). A quarter cup of rice, some soap water and 10 minutes of vigorous shaking made it shine like new! If you do that, wash it well: you don't want any rice in your coolant pipes.

Normally, the intercooler is supplied with Viggen hoses which are almost a direct fit. The custom made piping would've been even better. Unfortunately, I had neither, since my intercooler didn't come with any, and the stores were closed. So I decided to make the most of the stuff I had.

I had one extra elbow that helped to form the inlet section. The test fit looks promising.

The intercooler is put in place and the turbo hose is attached. This actually looks better than the Viggen hose, as the Viggen elbow forms a nasty bend on the T25 turbo, because the T25 is angled differently. And there's enough clearance even with the original radiator hose.

The new hose did not fit with the radiator fan frame, so I had to cut a corner of the frame off.

The fan is attached with two screws at the top. Everything seems to fit well. Make sure all clamps are very tight, especially if you used soap or another lubricant to put them on. You don't want any of those to come off on the road.

This is the hose from the intercooler to the delivery pipe. It had to be extended an inch and a half. The clamps are easier to reach from under the car.

The intercooler is not bolted on like the old unit, but it's held by the hoses quite firmly and is not going anywhere. I added strong zip ties on each side, as well as a couple of rubber strips to prevent it from rubbing against the radiator.

Time to fill the coolant.

Install the bumper, the lower shields, the headlights and the grille. The only sore spot left is my rusty license plate holder, which also blocks the intercooler.

The finished install: the plate has been replaced and attached higher, and the intercooler is seen through the opening in the bumper.