replace a radiator

Yup. It's the 1996 SAAB 900 again. As I pulled into a parking lot, white smoke began to billow out from under the hood. Oh yay.

Here is the exploded diagram of the cooling system.

I'm pretty sure it is actually the radiator. I could feel a hole I think.

Does anyone feel up to tracking down instructions on how to fix this? It will be a few hours before I  can do it myself.

Not necessarily a bad radiator.  A hole in a hose line, a stuck thermostat and a bad cap can all release white smoke/steam.  

When you say you could feel the hole, are you talking about steam escaping, a hole after the radiator cools to the touch?

Radiators are fairly straight forward.  I will give you the general stuff, but don't know Saabs or your specific model.

Drain the radiator.  
After it is cool to the touch, drain.  Have the radiator cap removed so it drains easier.  There is a petcock or valve at the low point of the radiator,  Usually on the bottom near the front grill.  It will look like a "T" upside down.  The arms turn to open and it drains from the center.  Catch the fluid in a pan.  Coolant is nasty stuff to animals.  It taste 'sweet' and destroys their digestive track.  Painful way to die.

With the radiator void of fluids/coolant, remove the upper and lower radiator hoses.  Looking at the inboard side of the radiator at the top and the bottom, usually diagonally to one another are inch and a half to two inch black rubber hoses.  (8 and 9 on your diagram.)  They are held on with metal band clamps.  Use a flat blade screw driver to loosen the nut on the clamp.  Back the nut off until you can slide the clamp freely way from the radiator.    Now the 'fun' part.  The hoses will likely be 'fused' to the radiator spouts.  You will need a screwdriver or a heavy pick to slide under the rubber and work the hose back and forth until it loosens.  It sometimes takes a lot of force.  Don't be afraid to damage/destroy the hoses.  They should be replaced anyways if they have not been for a while.  If you feel you need to reuse them squirt some water and liquid dish detergent under the hose and keep working with the screwdriver to get the hose free from the barb.  If replacing keep in mind the same process will need to be repeated at the other end of the hose.

Often the radiator hoses are run through or around the serpentine belt.  Poor design, but the limited space behind the radiator forces engineers to route it however they can.  If replacing the hoses one does not need to remove the serpentine belt, but do note the route of the hose and take some pictures to re install the hose where it will not rub or be damaged by moving parts.

Now you are past the hard parts.  The radiator is usually just connected with 4 bolts (1, 2, 3 on diagram)  Once bolts are removed it should pull straight up out of the engine bay.  Some cars have less space than other and you may need to pull compressors, alternators, relays, etc... to make room.  Don't know about Saabs.  You should not have to remove any body panels, grills, or other exterior parts of the car.  It should be able to come out with some coaxing.  When putting a replacement back into the engine bay, be careful not to bump the 'fins' of the radiator up against things.  The small tubes/capillaries behind them are easy to damage and that is how you get a leak in a  new radiator.  Be gentle and take your time.  Reverse the process.  Use detergent mix to lubricate the new hoses to slide over the barbs.  

Make sure the new petcock is closed and cap removed.  refill the radiator  by pouring equal parts coolant and water.  The exact ratio will be on the coolant bottle, but usually half and half gets one close.  After everything is filled and cap replaced (make sure it is seated properly and tight.) start the car and let it come up to temperature.  While it is warming, watch for leaks or steam.  If it is all good, let it cool again so you can remove the cap.  Restart the car and let it idle for a few minutes with the cap off to 'burp' air from the system.  Don't let the car over heat.  Water just needs to circulate for a few minutes to push out all the trapped air.

A few notes before you pull the radiator.   First, runt the car until you see white smoke to try to locate the source.  A pinhole in a hose if far more common than a hole in a radiator.  (don't forget the two hoses on 14.  They can leak too.)  Second there is a housing at the end of the upper hose. (14 on the diagram I believe.)   It is usually roughly triangular and has three bolts.  By removing these bolts and taking the cap off (where the upper radiator hose attaches) you will find a thermostat.  This has a spring and plate.  This will close when the car is cold allowing the hot water to recirculate and get hot.  Then it will open under the building pressure allowing hot water to travel to your heater inside the car.  Thermostats stick as they age.  If they stick closed, you car will over heat.  

After you check for leaks in the hoses, pull the thermostat out of the house and put the cover back on with the three bolts.  Run the car.  If it does not over heat then you have found the problem.  Thermostats are much cheaper than radiators.  Test the system with it removed.  Running the car with the Thermostat out won't hurt the car for testing purposes.  (replace it or the car may not get to operating temp and you will have not heater.)

Summary:
Check for leaks while the car is running and hot (shut down before it over heats.  be careful not to burn yourself.  Steam is not always visible at the leak.  You can run you hand past it while it is vapor and get burned before it turns to white smoke.

Pull the thermostat and run the engine.  If it runs normal, replace the thermostat.

If you can't find a leak in the hose and thermostat is good, before you replace the radiator go to an auto parts store. Ask at the counter for "Bar's Leak".  They will know what it is.  Pour a bottle of this sealant into the radiator to see if it will plug the leak.  Use the recommended amount.  More may not be better.  You don't want to seal up capullaries completely.   I save a $600 radiator replacement in a diesel truck using this stuff.  I have used it a couple of times.  It actually has a decent success rate.  That diesel truck still has the same radiator with the Bar's Leak in it from 2010.  It is an inexpensive fix that  may work.   If it does not, you had to replace the radiator anyway

Hope this helps.  

NOOOOOOOO. not the Saab!  Steam from the top or bottom? Could you tell? Did the car overheat before the release of steam?

Jack, thanks for the detailed instructions. I did find instructions specific to my car as well. Your info made some of my info make more sense. I will post them later on so I have a reference for the future.

More details. I did not have any prior overheating issues. This was a sudden and catastrophic occurrence as I pulled into the parking lot. I looked at the hoses as best as I could after it cooled down. They seemed fine. Though I did not try to remove them for a thorough look.

There is what appears to be a thin plasticy protective barrier between the radiator and the engine bay. My hole is actually a 4"x5" ish panel? low down, where the water was gushing out. We tried to track down the leak by pouring water in. It gushed out through this area, low down, toward the engine bay. So I think it is either a very large hole in the lower hose or the radiator.

At the moment the car is 40 miles away, waiting for help to get it towed back home. We went ahead and ordered a radiator, we expect it to arrive Saturday sometime.

Don't worry. A radiator is about the easiest thing to replace under a cars hood. Trust me, I have a curse that forces me to replace at least one a year for some damn reason.

No lie, I found a big leak in my trucks YESTERDAY....

Did I answer all the questions ya'll asked?

The WIS instructions are here.

Here are pictures of replacing the intercooler, that I do know is not the radiator, but some pictures may be useful to me. Replacing the radiator does not include removing the bumper. However, putting my tow bar on does.

My suggestion would be to consider the entire cooling system. It might be worth flushing the whole system. Since you need to drain the coolant anyways maybe it is worth replacing the thermostat at the same time. If the condition of the coolant is unknown. It is probably worth flushing the system a few times to clean it out. I need to change a radiator hose on my truck and will replace the thermostat at the same time along with the coolant..

Here is a good video on the process.

Okay. We'll flush it. The thermostat will have to wait though.

And somebody reccommends a line wrench? What do yall think?

Hmmm....

I can't find the thermostat on this car. I  know that it has to have one. Help?

Joylynn Hardesty wrote:Hmmm....

I can't find the thermostat on this car. I  know that it has to have one. Help?

based on the info you provided in the replace an alternator thread.

this is what you need https://www.esaabparts.com/viewparts.php?searchpart=1§ion=1110072

Joylynn Hardesty wrote:Okay. We'll flush it. The thermostat will have to wait though.

And somebody reccommends a line wrench? What do yall think?

Line wrenches work well. If you do not have one, you can try using a normal box open end wrench. Please be careful as it will not grip as well as a line wrench. Normal box end wrenches can slip and round the end of the nuts. If needed you can always borrow a wrench from someone, and if needed buy a set of the tools. I know if i needed one i could ask people in my community.

Thanks  Jordan! You're awesome!

Dan Fish wrote:Don't worry. A radiator is about the easiest thing to replace under a cars hood.

Well... no. See what the Saab Workshop System told me to take out. Sigh.

I am shocked beyond words.  At least words than can be repeated in polite company.    I am sorry you had to go through all that.  Yes, turbos and intercoolers make things more complicated; but that is ridiculous!  

I knew it was gong to get involved, you are really learning about that particular model.

We've gotten most of it back together. For making it go go, we just have one intercooler hose, battery tray and battery left.

The instructions say to check for leaks before every thing is together. I  have to assume shops have a cool dohicky that applies pressure to the system. We think it dangerous for the motor to start it up without all the stuff in the car. Here is hoping we get it all right.

Tomorrow will be the refilling and testing. Assuming all is well, headlights and the bumper go back on too.

Seriously, I cannot imagine getting the radiator out without all these things removed.

In related news, we were required to remove the air condenser and reservoir. So much for air conditioning in the car. Dammit.

AND the fan isn't working now.

Hunny cobbled some test wiring and verified the fan does work. We gotta take it back out and he'll redo the wiring. Right now there are bare portions. SHIT!

Speaking of bare portions, we found a bare spot ot the hot battery cable too. I had looked, but I missed that during our alternator adventure. Spendy. It's around 8 feet long.

It's out, and being worked on. I've been sent to find out what fuse and relay runs the fan. Does anybody know?

Hmmm... Is the relay in the plug attached to the fan?
A relay. Wrong model, but right info? In this parts list, it claims the relay is included with the fan.

On mine, what I would call the plug has something that looks like that. But the fuse is purported to be included too. It goes in a fuse box...

EDIT: Ummm... yeah. the relay goes in a box too. Hunny knew but was outside.

And the answer is in the owner's manual that I downloaded, probably from here, ages ago and forgot about it.

I intend to update with info for other poor sods stuck with this job, and access to a search engine.

The fuse is shot, How do we tell if the relay is good or not? By the way, there are two locations listed for relays.

Is it a four prong relay?  85 is ground, 30 is power in, 87 goes to fan, 86 is the trigger wire. On a 5 pin the numbers would be the same and you would ignore the 5th pin for now.

ummm... Are you speaking english?

By the way, for those following along, one might ask the car for some of this information.


Relay D FAN LOW



Relay I Fan HIGH

If you look at the prong side of the relay you will see the tiny numbers I mentioned. Bosch and Hella relays are interchangeable if the number of posts are the same.
I come up with that four prong as the fan relay. Is there another one similar in the relay box (another four prong)? If there is, and you can identify the accessory that it controls, swap the bad relay in question and see if it operates that accessory. If the other accessory works with your supposed bad relay you have proved it to be good. The emission relay and ignition relay should have 4 prongs. https://www.saabscene.com/threads/radiator-cooling-fan-problems.140815/#:~:text=In%20the%20relay%20box%20in%20front%20of%20the,the%20relay%2C%20arranged%20north%2C%20south%2C%20east%20and%20west.

Thanks! Is there a way to know if the relay is 4 prong without removing it?

With the numbers off of the relay a simple google inquiry would do it. So there are only a few components in line with the fan. You have tested the fan by doing the wire around. The relay, fuse and the temperature sensor that tells the fan to come on when the coolant gets hot. Did the car get up to temperature and then the fan didn't work or were you expecting the fan to come on immediately?

The car did get up to temperature and then the fan didn't work.