Technical Uno radiator level

[UnoMia]

Hi Everyone & Happy New Year!

It's been a while since I last posted on the Uno forum, my Uno 1100 has been running well - touch wood!

Last weekend I decided it was time to change the radiator coolant, it had been about two years since I last did it and it was looking a bit brown. I drained the rad and removed it from the car and back flushed it with plain water, I also put the hosepipe into the lower hose and let the plain water run until it came out of the disconnected hose from the inlet manifold to the heater. All eventually ran nice and clean, so I reassembled everything and refilled with a 50/50 mix of green coolant and distilled water.

My question is this: how full should the water level be in the side tank that is part of the radiator? There is a 'min' level mark on the tank but no max level. I would think that as it's an expansion tank then the coolant should be about three or four inches from the top of the tank, to allow for expansion when hot. Am I correct in thinking this or should the tank be filled to the very top with coolant? I have also noticed that since flushing and refilling the water in the tank is actually quite brown, not the nice green colour that it was filled with. Could this just be some rust that was stirred up in the block when I ran the water through it? I really hope it's not a sign of the head gasket leaking oil into the system now!

Any advice would be much appreciated. Thanks.

 

[Most Easterly Pandas]

I take it you flushed the whole system and not only the radiator

 

[UnoMia]

I flushed the whole system, (heater, etc), through with fresh water from a running hosepipe. I let it flow until the water ran clear.

 

[Most Easterly Pandas]

I flushed the whole system, (heater, etc), through with fresh water from a running hosepipe. I let it flow until the water ran clear.

How many times, with engine starts inbetween

 

[UnoMia]

Flushed it twice, after the first flush drove it round the block to warm the motor up, then let it cool right down, drained it again and flushed again. Finally refilled with 50/50 green coolant and distilled water. I don't like to use a flushing agent as I had a bad experience with the stuff on another car years ago.

 

[Most Easterly Pandas]

Flushed it twice, after the first flush drove it round the block to warm the motor up, then let it cool right down, drained it again and flushed again. Finally refilled with 50/50 green coolant and distilled water. I don't like to use a flushing agent as I had a bad experience with the stuff on another car years ago.

Sounds like you done well and correct, although I'd have drained it hot as thermostat would still have been open to aid in draining then

 

[UnoMia]

Thanks. I have a feeling that the brown stuff I keep finding under the radiator cap every day is oil in the water. I've got a suspicion that the head gasket is letting oil into the water slightly. Now I'm thinking I should pull the head off this weekend....

 

[maxi26]

Hey bru, i have the same problem. I recently did the complete engine,had the head welded and complete gasket set. after 5months, oil in cooler under the cap. I did the same what you dd recently by flushing the system. i hope its jst loosening and putting in n gasket.

 

[UnoMia]

Hi there,
I know what you mean! My Uno still has this brown, 'coffee', like stuff in the radiator filler tank but the car is not loosing any water, nor is it overheating and the engine oil level is not rising or milky in colour - it's really weird! The car drives well, (except for a suspected, unrelated clutch problem), it has plenty of power, pulls well, so I really don't understand where the coffee in the rad is coming from. If I ever find out I'll post the answer here.
Thanks to all for the replies.

 

[UnoMia]

Just an update on my coffee in the radiator story from earlier this year.
I ended up pulling the head off as the problem was getting worse and I was getting some water in one cylinder. Attached are pics of the state of the head. As you can see its badly eaten away around the water galleries and on one cylinder its almost broken through into the cylinder. The thing is this was a new head just 35 000km ago! I've always used the correct coolant mix, so it's not been running on plain water.
I had the head welded by a specialist company and lightly skimmed. It's all back together now and my new problem is bleeding the air out of the system as it's running a little bit hot at the moment.
Just been bleeding the rad again and this time got lots of air out, will now let it cool and top up before driving it to see how the temp is. Fingers crossed!

 

[Louie Bee]

not seen green coolant, but it looks like it's eaten the head!

I've only ever used blue or red

 

[EssexUno]

Yea same here Louie, at my garage the basic ones we use are blue or red, i put red in mine as it has better rust inhibitors and requires changing less frequently, if you get that head re-welded or get a replacement head then i would suggest that you put in a rust/corrosion inhibitor to stop it from happening again.

Dan