All 9-5 owners in the US market know the Coolant By-Pass Valve is a failure prone part. Although I had a spare valve in my trunk, I felt the likelihood it would fail in my driveway on a warm sunny day for a second time was pretty low. So to prevent the possibility of a roadside breakdown I decided to completely eliminate the valve by installing the european heater hose kit.

The part you need to do this exchange is #54-63-252 It is normally sold in the US by eEuroparts, RM European, saabpartsonline.com (Flow Saab out of Winston-Salem NC), Jim Ellis Saab's on line ordering system (Atlanta GA), and maybe a few other sources.

You will also need four new hose clamps; one 1-inch, two 1-1/8 inch, and one 1-3/8 inch. You can always re-use the old double tang style but most owners prefer to install worm gear style clamps.

You will need to remove the old Coolant by-Pass Valve and the three hoses connecting the engine to the CBV/heater core. Four additional hose clamps need to be removed, two of these additional hose connections are on the firewall, one on the firewall side of the engine beneath the thermostat, and the largest one on the end of the engine below the temperature sensor.

In addition you must disconnect the vacuum hoses from the solenoid valve to prevent vacuum leaks, BUT you must leave the solenoid valve electrically connected to the car's wiring harness. Disconnecting the solenoid electrically will cause lots of error codes from the detection of an open circuit by one of the many on-board computers. To disconnect the vacuum lines remove the Tee feeding vacuum to the solenoid, and replace it with a straight barbed fitting.

After eliminating these parts and replacing them with a $30 to $38 european heater hose kit; I now never have to worry about my CBV failing, I now never have to worry about my 12 year old heater hoses with 307,000 miles of use failing, and I spent less than the cost of a new CBV!

So the European models don't have a CBV at all? Or was this a modification only available in Europe? I never heard of this before and wonder what the CBV actually does at all if it can be eliminated.

The CBV is factory equipment only on cars with Automatic Climate Control, or ACC. Cars with Manual Climate Control (MCC) do not have this added part. All US Spec cars came with ACC whereas it was an option in many other parts of the world.

The only thing the CBV does (besides fail without warning and dump your precious engine coolant onto the roadway) is to by-pass engine coolant around the heating coil in the HVAC system whenever the ACC calls for Maximum Cooling. When by-passing the engine coolant the HVAC system sees a small increase in cabin cooling capacity. But since cars with MCC have adequate cooling without this added complexity, the advantage is unnecessary.

My ACC still works fine with the CBV removed (it is nearly 100 degrees Farenheit in S-E Michigan today). I still have the solenoid valve connected electrically, although it now does nothing, and is tied up out of my way in the engine bay. The non-CBV heater hoses occupy less space between the firewall and engine which may make other maintenance and repair work (i.e. replacing the rear hydraulic engine mount) somewhat easier.

I should have taken a photo of the old parts I removed lying next to the new hose set that was replacing them. Substantial difference! My wife was shocked when she stepped into the garage and I told her the clean tidy hose set was to replace all of the dirty parts lying next to them.

This is fantastic as I have leaking CBV right now ( just found out yesterday ).

Originally Posted by Rajiv

This is fantastic as I have leaking CBV right now ( just found out yesterday ).

Buy or borrow a pair of cable actuated hose clamp pliers as this will make the job MUCH easier. The two hose clamps tight against the firewall are still hard to remove due to location and the required angle of attack to remove the clamps. Removing the battery will give you easier access to the one hose connected to the end of the engine.

NOTE! - After posting my original message I discovered this will only work with the L4 engine. There is no equivalent part number for the V6 engine, and owners of V6 equipped cars will have to retain their Coolant By-Pass valves.

While researching this, I have also heard that this same part is used in other GM vehicles as well. one example would be Cadilac Catera. price for same part as Caddy catera is much cheaper ( ~$30 is what the thread mentioned ). since my CBV is leaking now, I am tring to decide between..

1. Bite the bullet and buy the part from local saab dealer. ~140/- or so
2. Test the hypothesis that part for Cadilac catera will be exact replacement
3. order the Coolant bypass valve bypass hoses like you and others have done and pray that my CBV does not completly give up the ghost before it arrives. part number you mentioned in your first post seems to be out of stock at eeuroparts.com as of this morning.


Any words of wisdom for saab newbie?

Have you tried any of your local (or not so local) Dealers to see if they stock the hose set?

The Cadillac part is identical and may be available from auto parts places in addition to GM Dealers.

I definitely would not pay $140 for a SAAB valve if the Cadillac part was available at lower cost.

Some owners have temporarily substituted barbed plastic pipe fittings for the valve while waiting for the correct parts to arrive. You can blank off the hose connecting to the lower left port on the valve, and tie the upper left to the right side hose with a straight connector. See photo I "borrowed" from another site.

gmpartsdirect.com has that part for $54. unfortunately rate of leak seems to be growing so I don't want to wait for too long. local Caddy dealer had it for $98 ( still $40 cheaper than saab dealer ). so went with that. I will be try and do this tonight and then keep looking for mackay hose kit when it becomes available. I did check at Aktive motors as well. they had it for $98 as well, but didn't have the part in stock.

I'm glad I looked at this thread, with 2 '04 Aeros in the family, 1 spare HCBPV, and what seems to be an ever growing back order list from Saab, it seems like a smart way to go and just get rid of the problem all together. I just went on eEuro and was unable to find the hose there, but just ordered one on Saab Parts online for $37.87.

I have exactly the same coolant leak problem. After having read everything on coolant leaks on the Saab 9-5 that I can find on the internet, I'm 99.9% certain that the CBV is the culprit. Instead of going to the mechanic, I decided to tackle the job myself as it seems simple enough. I have all the parts and tools I need, including the special hose clamp pliers.

My contribution to this post is just to let people know how you can get hold of a new CBV part cheaply and quickly. I decided to go for an after market replacement part but wanted to be sure that i get a good quality part so I thought I would get a brand name part from a German manufacturer (I have the utmost confidence and faith in German built machines). As far as I know AC Delco and Febi Bilstein are both German manufacturer who make the CBV part. Frank Wulfers here has the AC Delco CBV here for sale at the marketplace on this site for $30 which is the best deal you can find. I got my Febi Bilstein CBV from Amazon.com, it says made in Brazil but that's ok. Here are the shortened links:

Febi Bilstein CBV here: Amazon.com: Febi-Bilstein Heater Bypass Valve: Automotive

Pneumatic hose clamp pliers here: Amazon.com: Astro Pneumatic 9409A Hose Clamp Pliers: Home Improvement

The price for the CBV is $42.75. The cool thing about ordering it from Amazon is that I just signed up for a free trial of Amazon Prime where they will get pretty much anything to you in 2 days, free shipping with no minimum orders. And sure enough I got my CBV in 2 days and my pliers ($32), from a separate order in 2 days as well, free shipping in both cases.

Originally Posted by juze

I have exactly the same coolant leak problem. After having read everything on coolant leaks on the Saab 9-5 that I can find on the internet, I'm 99.9% certain that the CBV is the culprit. Instead of going to the mechanic, I decided to tackle the job myself as it seems simple enough. I have all the parts and tools I need, including the special hose clamp pliers.

My contribution to this post is just to let people know how you can get hold of a new CBV part cheaply and quickly. I decided to go for an after market replacement part but wanted to be sure that i get a good quality part so I thought I would get a brand name part from a German manufacturer (I have the utmost confidence and faith in German built machines). As far as I know AC Delco and Febi Bilstein are both German manufacturer who make the CBV part. Frank Wulfers here has the AC Delco CBV here for sale at the marketplace on this site for $30 which is the best deal you can find. I got my Febi Bilstein CBV from Amazon.com, it says made in Brazil but that's ok. Here are the shortened links:

Febi Bilstein CBV here: Amazon.com: Febi-Bilstein Heater Bypass Valve: Automotive

Pneumatic hose clamp pliers here: Amazon.com: Astro Pneumatic 9409A Hose Clamp Pliers: Home Improvement

The price for the CBV is $42.75. The cool thing about ordering it from Amazon is that I just signed up for a free trial of Amazon Prime where they will get pretty much anything to you in 2 days, free shipping with no minimum orders. And sure enough I got my CBV in 2 days and my pliers ($32), from a separate order in 2 days as well, free shipping in both cases.

I think you missed the point regarding this thread......

Originally Posted by photousa

I think you missed the point regarding this thread......

Most definitely! I will be waiting to rid my car of Dexcool for G05 until I have the CBV hose replacement. I hot on the trail a acquiring one.

Please help. Today I changed my coolant bypass valve, as I was changing and I broke to vacuum lines. They were fairly brittle and need to be changed anyway so I wasn't too upset, the only problem is I completely have no idea where that came from. I have looke at different diagrams to help with this matter but I have not been able to figure it out. If anyone can help me with the diagram of the lines that connect from the turbocharger all the way back to the cbv i I would really appreciate it. By the way I have a saab 95 4 cylinder turbo

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Here is one diagram of the vacuum line routing for the Turbo By-Pass Valve. Use 4mm silicone vacuum line to replace the old brittle rubber line.

BTW - eEuroparts stated two weeks ago they have a new source for the hose set that replaces the Coolant By-Pass Valve since apparently MacKay stopped producing this part. A spokesman for eEuroparts said this company is actually the OEM supplier for these hoses which were installed on all 9-5 cars without the ACC feature and should be available in another month. I've got a set on reserve for my '08 Aero.

Originally Posted by MI-Roger

[IMG][/IMG]

Here is one diagram of the vacuum line routing for the Turbo By-Pass Valve. Use 4mm silicone vacuum line to replace the old brittle rubber line.

BTW - eEuroparts stated two weeks ago they have a new source for the hose set that replaces the Coolant By-Pass Valve since apparently MacKay stopped producing this part. A spokesman for eEuroparts said this company is actually the OEM supplier for these hoses which were installed on all 9-5 cars without the ACC feature and should be available in another month. I've got a set on reserve for my '08 Aero.

Hey Roger, Thanks for the heads up, do you have a link for that hose set? How did you go about reserving a set with eEuro parts, just place the order and wait for it? Thanks

I told a Rep from eEuroparts who posted on another Blog to put me on the waiting list for one of these hose sets. I am not sure how much strength is in that request/promise so I intend to keep watching their web site and place an official order as soon as the part appears. In this Rep's post the comments were made regarding the new company being the OEM supplier and a target date for receipt 6 weeks in the future, which will be early September.

Thanks again, I'll send my contact there and email and try to get on the same list. I contacted a sales rep for McKay looking for that hose set months ago and they would just never get back to me, so after a couple of emails, I had given up.

No need to replace the valve. Just disable it. I have disabled mine for 3 years and so far so good. All you need to do is pull the vacuum hose that goes from the valve to the solenoid and put a plug on the solenoid nipple. Takes about 20 seconds and largely achieves the same thing as the McKay hose for pennies and much less hassle.

eEuroparts has these hose kits in stock again. Only three left in the warehouse after I ordered mine but they say more are on the way. I believe the price is lower than before. When was the last time that happened?

Thanks, I got one too.