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Discussion Starter · #1 ·
Hi all,

I recently noticed the engine coolant appeared to have a brown mousse floating on top of it. On inspection the coolant appeared brown. I drained the radiator from the valve and the coolant that drained was quite orange and had bits floating in it. I refilled using Holts SpeedFlush and water and then ran the engine for 10 minutes at full temperature. I drained, flushed with garden hose and refilled with water, then ran the engine again for 10 minutes with heaters on as per instructions. The coolant that has drained out of the radiator is still orange/brown, as I assume that this is what is trapped in the engine block when I drain the radiator.

I am not sure whether to refill the system with antifreeze now or try to remove the thermostat to do a full flush of the engine block. The only problem is I do not have a car jack other than a tyre jack so struggle to get underneath the car, whilst it is on my drive. Is it possible to remove the hoses from the engine block to flush it without lifting the car or is this something that I need to get the garage to do for me? (I was trying to avoid paying out). Any advice would be really helpful, as I've not done this before!

Many thanks

James
 

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Had it been sat for a while doing nothing? Also when you say coolant appeared brown, Was it water inside or coolant? You could have possibly picked up rust from rad if it was water/or been sat for a while.
Also how much flushes did you do? Ive seen 3 or 4 flushes still coming out dirty before.
 

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Discussion Starter · #3 ·
Thanks for the reply. It's had two flushes since the SpeedFlush agent was put in. I can keep trying but having discussed it with my dad he thinks that there might be a thermostat problem as well, as it is taking a long time to get up to temperature (15-20 minutes or so)? Could the thermostat valve be getting stuck? If so, why isn't the engine block draining too when I bleed the radiator? I'm a bit confused!
 

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On my Merv when I drained my coolant only 3.5 litres drained out from the 7.5 litres that the system holds.
Another litre lurks in the heater matrix.
I would just keep flushing it until you get to a stage where you are happy to put antifreeze into it.
 
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As above keep flushing, also have a check under ur oil cap, if ur gathering mayo could be another sign ur stat isn't working properly, with it being cold it will take a while to get up to temp but not that long
 

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Mine takes absolutely ages to warm up too.
I've still got my blanking plate in place in front of the radiator to help it along.
 
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Replaced my thermostat recently on the meriva it's not too difficult you will need to remove the battery and tray to get at it tho. Once the thermostat was changed I got heat through very quickly. keep flushing till your happy.
 

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Did you do it twice?

Must get round to replacing mine, even in the winter with most of the radiator blanked off and the heater on full I never get really hot air out of the heater.

Hood Automotive exterior Bumper Vehicle Car
 

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Yup did it twice, infact I had to do most jobs twice that day :rolleyes: due to a leak that was not so easy to spot until the thermostat was changed and the car up to temperature. The inside gets toasty fairly quickly now.
 

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This question of heat into the cabin from diesel engined vehicles crops up a lot , a diesel engine is a compression ignition type engine , the Big Bang so to speak is achieved by compression of the injected diesel & air mix , as it compresses the mixture it gets up to a very high temperature to achieve the combustion needed to run , the diesel engine has the highest thermal efficiency of any combustion engine due to its very high expansion ratio & lean burn which enables heat dissipation by excess air this is why it takes longer to get warm air into the cabin. My Astra takes a good 5 miles or 20 mins to get warm air out of the heaters , the wife's petrol juke is blasting warm air out after about 2 miles max , once the Astra is up to temperature she keeps the cabin hot in fact so hot i very rarely go above half way on the temperature control .
 

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Discussion Starter · #11 · (Edited)
Hi again,

Well I've continued filling and flushing and have attached a picture of the colour of the water still coming out after the 4th flush - it really is still quite grotty, but I'm persevering. I'm not sure what the coolant ratio was prior to me draining it, but it can't have been very high given the amount of corrosion. Quite annoying as this was supposedly checked and replaced when I had a full service around a year ago.

I'm not so sure there is a thermostat problem now, as there are no signs of anything untoward under the oil filler cap. 4 mins of revving on the drive at 3k rpm allows Merv to hit 85 degrees (without heater on). Temp stays at this level when left to idle. I'm getting warm air from the vents within a minute of revving from cold. Do you think thermostat needs replacing?

Thanks for all the help!

James
 

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Looks like you need to keep flushing.
Why not leave the drain tap open with a hose pipe running slowly into the header tank.
Might be worth flushing the heater matrix too because a lot of sediment collects in there.
Looks like you haven't had any antifreeze in there at all at one time for quite a while.
 
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Discussion Starter · #13 · (Edited)
Hi guys,

I'm still having problems with my Meriva's coolant, as it seems to be blowing out of somewhere. I lost about a litre of coolant after the car had been driven at speed, but this seems to only be intermittent as after I filled it, it didn't go down for a few days and then when I got home from work a few days later I noticed it was dripping on the road and that coolant had been sprayed across the engine bay (left hand side of engine bay - passenger side).

I think there is some oil getting in to the coolant, but not very much, as it has a slight shiny film on it. It would appear that there is also an oil leak, possibly related or unrelated, as I can see oil spots on our drive and when I look under the car there is some oil collecting on the lowest point in the middle of the engine. Researching online suggests that it could be the oil cooler that has failed? However I've looked in the Haynes manual and it suggests that I need to remove the exhaust manifold, by first removing the complete exhaust system and then the starter motor and the radiator?

Has anyone done this job on the Mark I 1.7CDTI? (Z17DTH engine), as I'm a bit of a novice mechanic but was willing to give it a go until I had a look at the Haynes manual, which completely put me off. Is there a need to remove all this or is it possible to change the oil cooler without removing as much?

Thanks

James

p.s. how do you remove the engine guard?
 

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Unfortunately on modern cars a lot of dismantling & removing of parts is needed to get good access to the part you need to replace , my Astra radiator took over 4 hours to do . Koicarpkeeper may be able to help you .
 

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The oil cooler is at the back of the engine so I don't see why you would need to touch the exhaust.
Facing the engine it is at the back on the right hand side.
With the scuttle panel out of the way and the bulkhead removed you can see it fairly well.
The two water pipes are easy enough to get to as well.
 
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