308 coolant change

There are two places that coolant must be drained from, (1) coolant hoses at the front of the car, and (2) petcock valve on engine block.

1. Under the front nose, there is a 2'x2' access plate that needs to be removed. Once removed, you'll see the coolant pipes.

2. Untighten the hose clamp on the lower pipe. Gently, stick a flat-edge screw driver between the aluminum pipe and the hose and coolant will begin to drain.

3. Next, loosen the thumb screw on the radiator (will allow coolant to drain quicker).

4. Remove the passenger side rear wheel well. On the rear bank near the #4 exhaust port, you should see a petcock valve. With funnel and hose ready, loosen the petcock valve and coolant will drain from the block.

5. When all coolant has drained from the block, radiator, and hoses, tighten all hose clamps in preparation to refil the coolant system.

6. Using DISTILLED water and coolant (I prefer Mercedes Benz coolant), get several containers of a 50/50 mix ready.

7. Start pouring coolant into the expansion tank. With an assistant on-hand @ the radiator, as soon as coolant begins to pee out of the thumb screw, tighten the thumb screw.

8. Next, have your assistant turn thier attention to the bleed screw on top of the water neck. Make sure the bleed screw is loosened. Begin pouring additional coolant into the expansion tank until coolant begins to pee from the water neck bleed screw. Tighten that screw.

9. Finally, fill the expansion tank to the level prescribed by the OM. I believe that to be 6cm below the fill hole.

10. You are done!

 

Before you start, pick up a Prestone radiator flush kit from an auto parts store.

The kit contains several sizes of T fittings with barbs on each end & a male hose fitting & cap. Once you've drained the coolant, cut the smaller coolant line that Ts (actually more Ys) into the large coolant line under the access plate & insert the T fitting. In the future all you'll ave to do is remove the cap from the T fitting.

 

The new fitting under the access panel will look like this:


this photo was taken before the clamps were positioned, and sorry it's a little blurry.
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The best thing to do is have it power flushed at a local radiator shop. They can do it while you wait. You would not believe the crap a power flush will push out of your cooling system. It cost me about $100 to have done on my Ferraris over the years.

 

Looks a little rusty underneath.

 

Hey Greg, on #8 where is the bleed screw. You mention the thumb screw and the petcock valve. Sorry for the dumb question. Thanks

 

Sorry for the confusion. Actually, it's not a bleed screw as much as it is a bolt that screws down into the water neck. One modification that many people have done is to drill a hole down the center of the bolt and then another hole width-wise. Then, you don't need to remove the bleed-bolt to perform this operation, or, relieve pressure.

 

I think he's referring to clarification of 'water neck' - its the large, brass bleed screw on top of the thermostat housing, no?

This bolt is not a 'true' bleed screw, as it is not slotted lengthwise through the screw's threads like the radiator bleed valve. The 'water neck' bolt is merely a bolt, and most all of it must be loosened to allow air to escape as the system is filled. This is tricky, because as you fill the system with coolant the air will weep out very quickly. One second there's air rushing out, and another split second you have a gusher of coolant spattering all over your engine. Because there's no lengthwise 'tap' within this screw, there's no 'happy medium' to this flow (unless you have an observant friend whose VERY quick with a wrench to tighten the bolt back in).

BTW, this is the EASY PART. PART II of this is to bleed the air out of the system so it doesn't overheat constantly.......in this step, you get to drench yourself in steaming HOT coolant, drop your radiator bleed screw down into your valence somewhere, and make a royal mess of your garage, driveway, and whatever clothes you have on at the time. Oh, wait, that must be ONLY ME who does this.....

 

M. James...good clarification.

As I mentioned before, one modification that many people have done is to drill a hole down the center of the bolt and then another hole width-wise. This creates a channel through the bolt so you don't need to remove the bleed-bolt to perform this bleed operation...you simply loosen the bolt and then there is nothing to drop.

 

Not positive but it may help if you turn your heater controls to the "full heat" position. I sure someone with more specific knowledge will let you/me know for sure.

 

can you post a photo of the access panel to take a look at it?? i am missing this access panel on my car ( 80 308 gtsi ) thanks.

 

Here is the panel:
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This access plate is at the front of the car, under the radiator? It's hard to get context from the picture. Thanks

Andrew

 

Yep- near the front. You can see the white battery in the first picture I attached. The panel is held on with a few screws, and the front is tucked under the back edge of the front spoiler- at least on my car which has the euro front spoiler.

 

It's actually behind, or to the rear, of the front spoiler panel....opne of mine is pretty beat up, I'll make a replacement soon, anyone else need one??

Man, I just rip the aluminum riser tube loose by the alternator, one clamp and ALL the coolant is on the shop floor! LOL!

Ya'll work too hard..........

 

Those orange scratches are in the rear of the front valance/spoiler panel......

 

thanks for the photo.

 

When bleeding the system be very careful about dropping the brass screw from the thermostat housing--it could easily fall in the area of the timing belts and being brass it won't stick to a magnet.

When bleeding the system, I found what worked best for me was to remove the bleed screws from the thermostat housing and the radiator and put brake bleeder screws with about 4 feet of clear vinyl tubing attached in there places. Put the ends of the vinyl tubes into empty antifreeze bottles and run the car for 15-20 minutes (until thermostat opens) while the system is bleeding thru the hoses into the bottles. When the bottles fill-up pour them back into the overflow tank. If the coolant is coming out too fast you can temporarily clamp the vinyl hoses with visegrips.

This way will ensure you get all the air out and you can see when it is clear.
Obviously when you have completed the bleeding operation replace the bleeders with the proper screws/washers.

Enjoy,

Mark

 

While that method may flush out the old coolant, it will not flush out the cooling system. Neither will a flush kit that you hook up to a water hose that you buy from an auto parts store. To get all the crap out of your cooling system you need a power flush that requires the use of an expensive high pressure machine that most good auto repair shops will have. When I had my ex-348 power flushed you would not believe the crap that came out even though the dealer had changed the coolant less than 6 months earlier. And,the car was less than 10 years old at the time. What do you think will come out of a much older 308 system? Spend the $100 and get the job done right!

 

JC whitney sells a power bleeder or something liek that to hook up to your air compressor , is that the "powerflusher"?

 

Can you recomend a shop in Atlanta to do this?

 

If I have the power flush done, do they still have to bleed the system or is it under pressure the whole time? I would guess the procedure is the same once the flush is complete.

 

I'll answer my own question. Today I had my radiator and cooling system power flushed. 'THe machine once flushing is complete fills the system under pressure eleminating the need to bleed the system. They did it anyway per my request and insistance. the coolant was air-less. I will recheck the car tonite just to be sure.