COOLANT LEVEL

I am flushing my coolant system and replacing the coolant on my 308 GTS QV. I have 2 questions. First, I am using the unmixed green coolant, do I use distilled water for the mix or will tap water work? 2nd question, do I fill the expansion tank at the back of the car to the top? Isn't the expansion tank the overflow on this car? Just want to make sure I get it right and I will bleed the system so there is no air. thanks in advance for your help.

 

Distilled would be better. Fill the tank about half full, it will spit out what it doesn't want/need. Bleed and bleed again. It will help if you park it on a hill/raise the rear of the car.

 

FYI: the reason not to use tap water is that there are minerals--especially calcium--in tap water that can deposit in your engine. This inhibits heat transfer, narrows the "arteries" slightly, and can also inhibit coolant flow if any of the calcium flakes off and lodges somewhere.

Distilled water is perfect, and rain water is okay, too.

 

Glad to hear the car made it safely to the 'Peg. Welcome to the joys of 308 coolant change (always messy)!

Regarding the expansion tank, it is true; the car will barf out what it does not need through the overflow hose. Note though, that the tank is naturally only about half full when cool. If you look in the Owner's Manual, it says the spec level is 6 cm below the rim of expansion tank filler cap. That looks almost empty when cool. Make a dipstick with the -6 cm level marked.

I find that too much is made about bleeding and rebleeding. Maybe the carb cars are different than the QVs or something. Now, I just bleed the front and bleed the thermostat and be done with it (okay, I bleed the rad once in a while; there is always air there but it never seems to get worse).

FWIW, BMW coolant is well regarded for its aluminum-friendly formulation; some BMWs have nasty-small coolant channels that sulfides can plug so they make good stuff. Always use distilled water.

David Helms makes a petcock pup hose for the front heater hose if you get tired of spraying half a gallon of coolant on the floor every time you drain the coolant system.

You done your fuel hoses yet???

 

Thanks Brian A. Great reply. Fuel lines were done by the previous owner. The rad was leaking when the engine is cooling down so I replaced it. The car is great. The only other thing was I'm flushing the brake lines and then we'll be ready for spring

 

One last one, once you have filled it & started it then open the heater valves & make sure you have heat coming out the vents - its very easy to get an air lock in the heaters.

If you do, sometimes it will shift itself (in which case you will need to top up the system) but otherwise you may find it easier to find a hose joint somewhere near the heater matrices that you can use to let some air out.

 

SUCCESS!. I filled the cooling system with coolant. Eventually, coolant came out of the bleeder valve on the radiator. I raised the back end and started the car, heat on full with the fan on high, car came up to normal temp, air bubbled out of the expansion tank to the bleeder funnel I purchased. I opened the bleeder on the rad again and it was all liquid. Engine fans kicked in at 192ish and inside was blowing very hot air. I ran the car for about 30 minutes. The engine after 25 minutes started sputtering and felt like it lost power, I presume because it was running hot already with no air circulation. I turn off the engine, removed some of the extra coolant from the expansion tank and then closed it up. I ran the car again for about 10 mins, fans kicked in and everything seems great. Here is my questions. Do I have to bleed the system again? If everything was working, should I just leave it and enjoy! Thanks for your suggestions, Cheers Barry

 

It takes a lot of bleeding to get it all out.
Drive it some.
Bleed it.
Drive it some more.
Bleed it.

The movement of the car and coolant with help get the pockets of air out of 'trapped corners'.
Every time you drive, you should bleed it.
You will find a little bit of air will come out.
And, when it stops coming out, you're done.

 

Sounds great. Unfortunately I can drive the car right now because its winter, so I'll have to make sure I do the bleed again when I take it out in spring.

 

Hi Barry,
I don't see in your write-up above where you bled the thermostat? There are two bleed points, the radiator and the bleed screw on the thermostat. Both usually need to be bled to get the air out of the high points in the system.

 

I couldn't get to the thermostat bleed screw however, when the thermostat opened, there was a rush of air out of the expansion tank. Heat and everything seemed to be flowing and working perfect. Do you think there will still be air in the system. It seemed like the heater core and radiator were bled. I'll bleed it again once I get a chance to drive it. I appreciate the help, I've never done this before and I want to make sure everything is proper.

 

I wrote the attached procedure after researching on this site. I am inclined to suggest bleeding at the thermostat is necessary. I agree it's a pain. With my car it means removing the bonnet and removing the air box in order to be able to reach the thermostat bleed screw.
View attachment CoolantChange.doc

 

Thanks Irishman. That's great. I will check the bleeder at the thermostat tomorrow.

 

"I ran the car for about 30 minutes. The engine after 25 minutes started sputtering and felt like it lost power,"

That shouldn't happen and has nothing to do with the cooling system…

Re bleeding. Maybe 308s are different but I have changed the coolant several times on our 328 and all it requires is filling the system, bleeding from the rad, then bleeding from the T-stat - as per the Ferrari instructions in the owners manual. It never requires additional bleeding and, IMO, if recurrent bleeding is needed, it is because there is a leak(s) in the cooling system. The expansion tank is just that - for expansion. As long as there is a bit of coolant in it when cold, that's sufficient. Having more than that does nothing for the cooling system since the cooling system is already full. OTOH, overfilling is not a problem - the car will just spit it out until it finds the correct level.

 

Wow, I lived 9 years in Winnipeg as a kid and loved it. Great town. I don't think I could move back there [in the winter at least] now that I have let my blood thin in the deep south for so long, but I still remember the great night skies and northern lights in the winter.

On my 84QV the thermostat bleed is definitely necessary. I found Verell's bleed screw for the thermostat casing to be very handy. Just crack it open a bit after the thermostat opens and off you go.

Also on my car at least, I find it took a few extra bleed sessions over the next couple of weeks from a fluid change to get all the air out. After that I just drive the car and other than ridiculously hot days in the summer down here have no probs.

Ciao,
Paul

 

Bleeding the thermostat gives you the opportunity to spew coolant all over your timing belts.
Yippy skippy.

 

LOL

 

I never bled the thermostat and the car ran perfectly cool through a hot Florida summer.

 

Do you guys bleed the system with the reservoir cap on, off, or just loose?

 

I bought a spill free bleeding funnel. $29. It attaches to the expansion tank and allows the air to bubble out of the system. It really helps when you raise the back end of the car in the air.

 

Cap off, but I may have a screwed up procedure.

My air bubble loves to live up front. 10,000 miles post engine rebuild and I have never had to add coolant, so I don't think it is a problem, but just the way the car is.

When I take off the cap after driving a couple of weeks or so the fluid level in the rear tank is at the top.

Then I open the bleeder on the radiator. Air hisses for 10-15 seconds, then burble of coolant. Close the bleeder.

I go back to the tank and it is at the prescribed 6 cm. I put the cap back on.

Someone suggested the air bubble moves in 10 seconds after I start, but just by keeping my eye on it it seems to take more like 2 weeks.

Like I said, I don't loose fluid, so I don't really worry about it much, just it is something to do for the preflight

 

Re periodic bleeding…

Does anybody believe that people needed to take their new 3x8s to the dealer periodically when they were new and in-warranty for "burping" service?

Fix the leaks!

Sorry, this is one of my rants…like the Doc's R12 rant.

 

If there were a leak, I can imagine how, as the coolant system pressure rises, coolant could be forced out, but I don't understand how air could be forced in. My understanding is that the coolant system pressure never drops below atmospheric pressure.

 

My 328 does exactly the same - always has.

 

Assuming the system has no leaks and is properly filled, air cannot enter or be "generated" in the system.

So if air does periodically appear in the cooling system, some possibilities are:
1. Head gasket leak - don't just think of a BLOWN head gasket, think of a slight seep…
2. expansion tank empty, allowing air back into the system when engine cools
3. pinhole leak in hose/sealing surface that is normally OK but opens under vacuum
4. slight actual coolant leak you are not seeing because it occurs only when driving at full operating temp/pressure; coolant "disappears" in the wind stream/engine heat. Engine cools - air enters via leak.

There is NO WAY for air to just "show up" in a properly functioning engine/cooling system. Something is wrong or the system was improperly bled when coolant/components were changed. Once bled, it will remain bled until the next time you need to change something…or until there is a leak.

Re the head gasket: a head gasket can seep at high load and be OK normally and show perfectly good compression.