Speculation: How long would it take for a bad HG/head to show itself?

OK so earlier this summer I was down south headed to a karting day with a couple of friends, a few miles from the track I decided to see if my EAT chip was actually good for ~7k in third gear on this lonely deserted country road. :p

So as I pulled into the track pitting area, not thinking anything of my car, the thermostat shot to red and I saw a metric ton of steam escaping from every nook and cranny it could find under my hood.

Turns out the main (largest) hose that runs to the radiator right near the top (drivers side M30) split loud and clear. I let my car sit and tore up the track, a few hours later I refilled with whatever OEM coolant I had with me and we attempted to make the return trip... I refilled three times with water because there was no way we were going to repair the hose and there was no way I was paying for an expensive tow out in bufu...

My procedure for filling was to wait until the car showed signs of shooting to red, pull over, let the engine cool down, and refill the expansion tank to the top with water.

I replaced the hose and about a week later I was driving around the inner city in Chicago when something similar happened to me.

Turns out the clamp that connects to the radiator had shot off when I replaced the ruptured hose and I was losing my coolant again. Reconnected that after the engine had cooled down, had no water so I attempted to make it the few miles home.

This is where I'm wondering if the engine sustained damage: I took the highway after reconnecting the hose and the needle shot almost immediately to red, the car threw an alarm about Coolant Temp which I had not experienced before, and I shut the engine off and coasted the shoulder for as long as I could til I could find a place with water... this probably happened two or three times before I could stop somewhere.

Fast forward to now: the past couple of weeks I have had the Coolant Level sensor throw off when I start the car, I refilled the expansion tank last week with 50/50 OEM coolant and I get the warning thrown at me again today.

Is it possible that something a few months ago could trigger what is happening now? I haven't started looking for leaks yet and I have my hopes that I don't have to do any major overhauling til I am at my home garage this summer.

Look now and avoid the bill later is all I can really suggest; A faulty cooling system will stress the motor, and an M30 with an old head gasket doesn't like stress at all. Check where the leak is occurring ASAP. After my experience I'd have to say I'm never keen to see my needle go North of half way, if it does I'm off the road.. I'll never run my car under load with the cooling system open enough to accept air. If it gets bubbles in the head (it'll create its own steam the moment u depressurise the system) this is what happens. Then coolant stops flowing. How long does it take to cook the head or blow the gasket? Only Buddha can tell you that dude... but your car is old enough to need it without going through the kind of experince you describe.

I wonder if anyone on the board has seen an M30 go past even 18 years of age without having it done... sorry I can't help more :) Nick

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Originally Posted by genphreak

Look now and avoid the bil later is all I can really suggest. A faulty cooling system will stress the motor, and an M30 with an old head gasket doesn't like stress at all. Check where the leak is occurring ASAP. After my experience I'd have to say I'm never keen to see my needle go North of half way, if it does I'm off the road.. I'll never run my car under load with the cooling system open enough to accept air. If it gets bubbles in the head (it'll create its own steam the moment u depressurise the system) thsi is what happens. Then coolant stops flowing. How long it takes to cook the head or blow the gasket? Only Buddha can tell you that dude... but your car is old enough to need it without going through the kind of experince you describe.

I wonder if anyone on the board has seen an M30 go past even 18 years of age without having it done... sorry I can't help more :) Nick

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Thanks for the reply Nick.

Don't worry about being helpful, you were without effort. This thread is merely speculation, I will take a look at it when I drive it (home) again in another week or so.

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Originally Posted by JAlfredPrufrock

Thanks for the reply Nick.

Don't worry about being helpful, you were without effort. This thread is merely speculation, I will take a look at it when I drive it (home) again in another week or so.

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Sure, no probs. Check in the oil for water before you do and try to cover as much as possible before you go. Be sure to look for water mixed in with the oil or just at the bottom of the sump before you start it up). If you have it I'd think twice before driving it... it might not last the trip. (Plus you'll need to budget for a new O2 sensor) once a fix is found... and that fix will be a head gasket. at least, its no picnic financially.

When mine went it was only blowing water the slightest of water out the side on a hot day. I got to it quick, didn't drive it hot for more than 10 seconds the first time the needle rose and my gasket replacement didn't involve any warpage in the head. That would make it much more expensive as you'd have to take it to a (BMW experienced) machine shop for that.. would take time too. Good luck :) Nick

In all this reading did I notice any attempt to bleed the system properly?

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Originally Posted by JAlfredPrufrock

Thanks for the reply Nick.

Don't worry about being helpful, you were without effort. This thread is merely speculation, I will take a look at it when I drive it (home) again in another week or so.

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Originally Posted by 632 Regal

In all this reading did I notice any attempt to bleed the system properly?

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Air in the system is not an issue at the moment.

it is if its overheating.

Is there a lot of comdensation coming from the exhaust? How about pressure in the system if you start it with the expansion tank opened?

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Originally Posted by 632 Regal

it is if its overheating.

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No overheating... but I've had to top off the expansion tank twice in the past two weeks.

your not helping without posting more details man.

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Originally Posted by JAlfredPrufrock

No overheating... but I've had to top off the expansion tank twice in the past two weeks.

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You know, one thing to remember is that overheating affects more than just the engine internals -- as you saw, the weakest point (that being the elbow pipe) blew out. Everything else in the circuit (including all electrical switches) were affected, as well. This is why I usually end up replacing most plastic components on the V8 cars when they blow a water pump and overheat.

First thing to do is to check the switch itself. Then, go from there. It could just be bad from being overheated.

best, whit