Gunk in header tank

[thecyrusvirus]

Hi everyone

I was getting ready to drain, reflush and refill the coolant on our 1.9dg today (we have only had her for 4 weeks) when I noticed some creamy gunk in the header tank - just a smear on the tank cap. I only took the cap off to pressure test it before starting the drain...and it doesn't hold pressure so a new one is on order.

I am more concerned with the oil in the coolant, I know it is an old engine and it had been sat unused for 9 months before we bought it. I don't know the history before that but it runs nicely since I sorted the ht leads, vacuum hoses and breather hose.

I also noted that the sensor in the header tank was disconnected.

I am not a mechanic but always have a go myself and have changed a few cylinder heads before (admittedly not a waterboxer) - I have read the horror stories of snapped studs etc

So, should I go ahead and get the heads off and check and replace OR is there another potential source of the oil in the coolant

Or should I slap some k-seal in there and see what happens?

Any advice, thoughts and opinions welcome..

[what2do]

If it were I, (I'm probably a bit more slack than most), I'd flush it and refill with water, run it to temp, drive it for a week and see what transpires. If all is good, flush again and refill with coolant. If things are not good.......come back and ask again.

[thecyrusvirus]

Cheers what2d, I just didn't want to put £40 worth of antifreeze in it just to have to replace it again in a few weeks!

I think I will go with your course of action...I wouldn't call it slack - more like prudent or thrifty perhaps

[what2do]

Exactly, it certainly won't harm to release half of the water out before topping up with coolant once you're happy that all is ok.

I've never thought to ask if it is possible to literally let some out slowly whilst someone else fills the reservoir up, without needing to bleed it.

Anybody have any thoughts on the process?

[CJH]

Personally I wouldn't want to run without the proper coolant for a week. Obviously you can't tell what's been circulating for the rest of it's life, but why risk making any corrosion worse. Drain it, flush it, and refill it with the proper coolant. If you need to drain it again you can collect it in a bucket and strain it for reuse.

[CJH]

You can do better than £40 for the proper coolant. I used this. You'll need 9 bottles, so just over £24.

[thecyrusvirus]

Thanks for the link CJH, I got mine from Eurocarparts but I ended up getting the G13 stuff which was slightly more expensive as it was the only one with enough stock at my local branch.

I guess this weekends job is the flush and fill then

[what2do]

Personally I wouldn't want to run without the proper coolant for a week. Obviously you can't tell what's been circulating for the rest of it's life, but why risk making any corrosion worse. Drain it, flush it, and refill it with the proper coolant. If you need to drain it again you can collect it in a bucket and strain it for reuse.

What exactly do you think may happen by running with just H2O for a week? A big far zero that is detrimental to the engine. By catching the fresh coolant in a bucket and reintroducing it again, you'll also be adding some of the gunk that you're trying to remove unless equipped with a magnetic/particulate filter.

[CJH]

What exactly do you think may happen by running with just H2O for a week? A big far zero that is detrimental to the engine. By catching the fresh coolant in a bucket and reintroducing it again, you'll also be adding some of the gunk that you're trying to remove unless equipped with a magnetic/particulate filter.

You're probably right, but since you're going to refill with that coolant eventually, why not do it immediately after flushing the system? I doubt that anything that would get through a paper-towel-in-a-funnel filter would be worth worrying about. Saves you sweating if you don't quite get around to putting the proper coolant in the following weekend too.

Out of interest, just how long does it take for corrosion inside an engine to get going - weeks, months, years?

[thecyrusvirus]

Is there a recommended product to help flush/ breakdown the gunk that I can add to the system before flushing through with water?

[what2do]

What exactly do you think may happen by running with just H2O for a week? A big far zero that is detrimental to the engine. By catching the fresh coolant in a bucket and reintroducing it again, you'll also be adding some of the gunk that you're trying to remove unless equipped with a magnetic/particulate filter.

You're probably right, but since you're going to refill with that coolant eventually, why not do it immediately after flushing the system? I doubt that anything that would get through a paper-towel-in-a-funnel filter would be worth worrying about. Saves you sweating if you don't quite get around to putting the proper coolant in the following weekend too.

Out of interest, just how long does it take for corrosion inside an engine to get going - weeks, months, years?

Now and again, I flush central heating systems. It's incredible how much discoloured water can appear in a matter of seven days. However, it's only minor corrosion compared to reintroducing coolant with the other associated 'bits' in it.

[what2do]

Is there a recommended product to help flush/ breakdown the gunk that I can add to the system before flushing through with water?

Yes, elbow grease! Look on the wiki about cleaning the pipes that are inside the top lip of the engine bay. Gunk tends to collect where there is a restriction, ie. small pipes, rad vanes and the likes.

Others will comment on system cleaning products.

[thecyrusvirus]

Good thing I have two tubes of elbow grease ready!

Although after smashing my elbow on the rear arch of my celica last weekend when trying to undo a seized caliper nut I might only be able to use one.

I shall read the wiki now