M42 issues: coolant flange being shit

[econti]

My coolant was pretty low a few weeks ago. As in, getting towards the bottom of the reservoir when cold. I've been driving it pretty hard, so thought nothing of it and topped it up with distilled water.

Checked again today, and it was down pretty low again.
There are no leaks on the ground, and the PO put a new radiator with hoses and everything in.

I have noticed that the temp gauge moves slightly around while driving, slightly as in it might sit a hair under half, then move to the lower part of that second quarter on the gauge, then back, things like that.

What's going on? Was it just air bubbles moving out that caused the level to drop the second time? Or have I managed to crack a head or blow a gasket? There's no milkshake in the valve cover, although opening the lid when it was hot let a small amount of steam looking stuff out.

My previous car was a MA70 Supra, and it used coolant because the head gasket was in the process of blowing. No milkshake either.

[Silver Wagon]

my guess is either cracked head, head gasket, cracked block or air bubbles. listed in order of likelihood. there is another thread somewhere where a dye was put into the coolant to see if exhaust gases were being introduced. that might be a way to check without pulling the head. also a pressure test of the coolant system might also reveal the issue. i'm new to M42's so this is based on what i have read up on them so fa, hence "my guess".

[econti]

Brilliant. Lots of expensive things.
Should I have bled the system when I added to it the first time?
I was told that the heads crack when they overheat, but it didn't overheat. So is that still a possibility?

[bmwman91]

Honestly, the best thing to do right now is to top the coolant off and go get an inexpensive chemical test from your local parts store to test the coolant for combustion gases. If that comes back positive, you are pulling the head, regardless of the cause. If it comes back negative, then maybe the system was improperly bled. You do not need to bleed the coolant after topping it off, but if the expansion tank ran empty at some point then you could have gotten air in the system.

I have seen the coolant level fluctuate by a few inches over the course of a year as the outside temperature varies, so maybe it has something to do with that.

Good luck.

[econti]

Honestly, the best thing to do right now is to top the coolant off and go get an inexpensive chemical test from your local parts store to test the coolant for combustion gases. If that comes back positive, you are pulling the head, regardless of the cause. If it comes back negative, then maybe the system was improperly bled. You do not need to bleed the coolant after topping it off, but if the expansion tank ran empty at some point then you could have gotten air in the system.

I have seen the coolant level fluctuate by a few inches over the course of a year as the outside temperature varies, so maybe it has something to do with that.

Good luck.

Alright, will do. Thanks man.

(Side note: Can't believe I misspelled losing!)

[econti]

So, the problem was this:



The leak only starts when the engine is hot, which is why I didn't catch it earlier. Also as most of it just vaporises because of the hot engine.

Ordered a new part, should be here on Friday.
Anyone know of a guide to replace it? I searched around but couldn't find anything.
I'd like to get an idea about exactly what I'm doing before attempting to fit large hands in small spaces

[anthonymax007]

So, the problem was this:



The leak only starts when the engine is hot, which is why I didn't catch it earlier. Also as most of it just vaporises because of the hot engine.

Ordered a new part, should be here on Friday.
Anyone know of a guide to replace it? I searched around but couldn't find anything.
I'd like to get an idea about exactly what I'm doing before attempting to fit large hands in small spaces

I replaced mine a few weeks ago. Not really sure if there's a guide or not, just make sure you look for any corrosion from the plastic pipe. I had a lot of gunk and crap where the pipe met the engine. I also had to replace the heater hose running from the radiator to that pipe as well. It's not tough when you have the intake and all that off. Buy new intake gaskets too, you'll want to replace them since you'll need to take the intake mani off. Might as well do the mess under the intake too if it hasn't been done yet. Here's a link to that:

http://www.m42club.com/forum/index.php?topic=2742.0

[econti]

I'm going to attempt to do it without pulling the manifold as I'm broke and don't want to buy new gaskets, and you can apparently do it in situ with a little patience and some ingenuity.
Would love to do the plate delete, the idle stumbles sometimes.
Once more money is in the bank, then that's the way I'll go

[roguetoaster]

You might be able to get it without pulling the manifolds, but you'll just make it a harder job on yourself. You don't always need to replace the gaskets when you split the manifolds in any case, just depends on their condition. As a last resort you can use RTV on them, but if you have to pull it back apart the gaskets will probably be ruined.

Don't forget to RTV up the TB gasket(s) as they won't be hurt by RTV, but are a frequent cause of small leaks.

[econti]

I'm in the process of trying to do it now. It's not working well with the manifold on.
Gasket goo ahoy!

[anthonymax007]

You might be able to get it without pulling the manifolds, but you'll just make it a harder job on yourself.

Yea I was going to say it's actually pretty tight down there. I've got little skinny girly hands and I needed to pull the manifold off to get the job done. Either way good luck and keep us posted!

[econti]

So I ended up taking the manifold off and doing it.
The old pipe was broken, so I dug it out and then put the new one in.
The new one didn't seem to want to seal against the block. I thought it was just how they were, and bolted it in and left it.
Now, I just filled it up, and it's leaking out of that hole.
What have I done?
Both the bolts are in, so it has to be lined up, right?

[roguetoaster]

This is the part where you take everything off again.

Pull the tube back off; inspect the seal for pinching; if good lube gasket; without placing either bolt push the pipe/seal into the block until you hear/feel a pop; reassemble the whole mess.

Sometimes it can feel like it won't seal, but it will with some cajoling and patience. If you damaged the gasket you absolutely should get a new one. Or if your budget if silly tight you might be able to use RTV to replace/reseal it, but I sincerely doubt the longevity of such a repair. OTOH, you will get removing the manifolds down to ten minutes flat.

[bmwman91]

Use a flathead screwdriver and steel wire brush to clean out the bore that the new water pipe needs to go into. You want to make sure that the rubber O-ring is sealing on a clean surface. And as roguetoaster said, you need to push that water pipe into place all the way. It takes some pushing, and I recommend lubing the rubber O-ring with some soapy water or silicone grease. It takes a hell of a push to get it in there!

[econti]

I thought that doing the bolts up would be enough to suck it in there? It was pretty rough though.

My least favourite part is taking things apart that you've just put together. All the fun of cut hands and bruised knuckled without the excitement of figuring out how things work.
I only have myself to blame which makes it even worse.

But who the hell thought it was a good idea to have a plastic pipe next to an engine block?