Strange way of fixing my car

[englisharcher]

Lately my car has been hunting at tickover, it's been reving anywhere between 1000 and 1400 RPM, but yesterday I was checking the fluid levels and it needed 3 litres of coolant, since putting the coolant in, tickover has returned to 800 RPM.

I've spent all night trying to figure out why coolant would fix a tickover problem, but I have come up with nothing, does anyone have any ideas?

[Kurtcobain]

3 litres of coolant.. Any sign of a leak?

[englisharcher]

No, and it is also using oil, I am looking for a replacement, but haven't found anything perfect for us yet

[Kurtcobain]

How much oil? Any mayo in the coolant cap? When starting up, what colour is the smoke that emits from the exhaust?

[englisharcher]

Litre of oil a week, and she is smoking blue, I know she is on her last legs! No mayo, I suspect it may be worn rings

[vetrof]

What car is it? Does it have a water temp sensor? Could give fluctuating temp readings to ECU.

[Kurtcobain]

Yup does sound like rings but for it to lose 3 litres of coolant without a sign of leak or mayo is strange..

[McSam]

englisharcher said:

Litre of oil a week, and she is smoking blue, I know she is on her last legs! No mayo, I suspect it may be worn rings

What's the car? I hope you have a replacement handy..

Also no clue where that coolant could have gone without a leak (are you sure?) or obvious steaming during running. If neither of these, it must be in the oil and would be generating serious signs..

[englisharcher]

Daihatsu sportrak, 1.6i

[BorkFactor]

My Astra used to burn a litre of oil every 100 miles and clog the spark plugs, pretty sure it was either the valve stem oil seals or the piston rings.

I ended up running it on Tesco Value 20w-50 oil for it's last few months as it was getting silly, then a local garage gave me £1250 for it (paid £1300 for it a year earlier) as a trade in

[angusc43]

vetrof said:

Does it have a water temp sensor? Could give fluctuating temp readings to ECU.

This is what it will be. The wife's Clio had a very rough idle. I dropped it off at local garage to get the crank sensor sorted. I also mentioned the rough idle. They spotted low coolant and topped it up. Idling immediately back to normal.

They reckoned it was a temp sensor getting faulty reading do to lack of coolant. This was then confusing the ECU which was trying to over-compensate.

[thinfourth2]

The coolant pump takes maybe 5bhp from the crank

When the coolant is low it will start losing suction and all sorts of other nasties hence it will need way less power to run it.

When the coolant is full the pump will operate normally with a constant load

[englisharcher]

McSam said:

yikes:

What's the car? I hope you have a replacement handy..

Also no clue where that coolant could have gone without a leak (are you sure?) or obvious steaming during running. If neither of these, it must be in the oil and would be generating serious signs..

Been thinking about this all day, the car is full of condensation, I've always assumed it was because of the removable hardtop, but now I'm thinking about a leaking heater matrix, what do you think?

Edited by englisharcher on Thursday 1st March 20:17

[Gallen]

Heater matrix for sure

[Jimmyarm]

It will smell quite 'sweet' in the car if the matrix is leaking, assuming there is some antifreeze in her