Is my engine dead if I drove overheated for few miles

I own 99 323I, it has 150k on it, I just love driving it. Last Friday morning, I saw the coolant indicator but drove it work with a plan to have the coolant filled near work (40 miles from home). One the way back home the coolant indicator disappeared, so I thought the indicator popped in the morning coz I took out the car after a week or so that too in the cold temp. So kept driving, the indicator popped on and off, suddenly saw the heat indicator on the extreme red, slowed down but kept driving (ignorance and stupidity) the indicator still on the right but not bright red. I may have driven for 5 miles with the heat indicator at its peak and finally car stopped. Got the car towed it to workshop, coolant tank cracked and they did compression and leak-down test. the results from leak down test are 1-10%, 2-15%, 3-18%, 4-25%, 5-15% and 6-5%. Do these results show that engine is no more good shape. Mechanic is suggesting to go for a different engine (lot of money though). based on what I read in forums leak downs around 20 are still Ok. but not sure, I am thinking of getting the coolant done and see what happens. What do you experts suggest.

Thanks in Advance
Kris

theres a lot you can do to these engines. but overheating? no way. especially the fact that you kept driving on an overheated motor, you couldve made your engine a cool centerpiece. i wouldnt bother adding coolant, or driving on it for that matter. i am not an expert, but im sure Fast Bob or those gents' will be here shortly

couldn't u just park it and waited on it to cool down or toe it instead?
anyways, damages could be from nothing to warped head, gasket problems,... to a dead engine
to check if you have a blown head gasket, check if white smoke is coming out from the tail pipe, and change ur oil. if there is water mixed with the oil, tough luck , if not, u'v survived this one
a simple diagnosis at a dealer should give u all the info u need.
for next times, whenever u see ANYTHING lighting up on ur instrument cluster while driving, PARK IT ASAP to avoid paying lots of $$$ when a simple pulling aside the road would save ur pocket and car alot of trouble

If you catch it right away you are usually safe. Aluminum does not like to get hot. If you drove 5 mikes in the red you are probably in trouble but who knows. Check it out, check oil and such. Wait for one of the pros to chime in here.

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Please update on your situation. I'd like to know how tough an E46 engine is.

I know my expansion tank cracked on me when I was 20 miles away from home. I quickly went to get distilled water and consulted Smolck who is to me, a knowledgable E46 guy at this site. He specifically said DON'T LET YOUR COOLANT GAUGE GO INTO THE RED. If it does pull over right away.

Since I knew it was just my expansion tank I knew I still had water in the system since I still had heat. I quickly started driving home slowly (with interior heat and fans on full) getting my car up to speed and turning it off as I coasted until 5-10mph lower then speed limit. I knew any chance I could turn the engine off, there'd me no pressure in the system to blow the coolant out even further. Good thing I have a manual I could clutch start it and never use my starter during this trip! I still had heat up until 10 miles to home then I started to slowly lose heat knowing coolant levels have now gone lower than the thermostat. That's when I knew I needed to pull over at a safe place to force feed my system the distilled water I bought at the store to return levels where the water pump could still circulate water. Never did my coolant change from normal operating temp as I coasted my vehicle home 50% of the time while accelerating 10-15mpg over speed limit. I never kept on the throttle to maintain speed, I only used it to keep speed up so I can coast. I successfully got home, quickly cooled the engine bay, popped the expansion tank off, put my old working one back on, re-bled my coolant system and went to a car meet 20 minutes after. LOL.

Originally Posted by isitkittu

I own 99 323I, it has 150k on it, I just love driving it. Last Friday morning, I saw the coolant indicator but drove it work with a plan to have the coolant filled near work (40 miles from home). One the way back home the coolant indicator disappeared, so I thought the indicator popped in the morning coz I took out the car after a week or so that too in the cold temp. So kept driving, the indicator popped on and off, suddenly saw the heat indicator on the extreme red, slowed down but kept driving (ignorance and stupidity) the indicator still on the right but not bright red. I may have driven for 5 miles with the heat indicator at its peak and finally car stopped. Got the car towed it to workshop, coolant tank cracked and they did compression and leak-down test. the results from leak down test are 1-10%, 2-15%, 3-18%, 4-25%, 5-15% and 6-5%. Do these results show that engine is no more good shape. Mechanic is suggesting to go for a different engine (lot of money though). based on what I read in forums leak downs around 20 are still Ok. but not sure, I am thinking of getting the coolant done and see what happens. What do you experts suggest.

Thanks in Advance
Kris

My logical advice is to have the expansion tank replaced, which parts and all should be around $100, and go from there. If after doing that everything seems to be fine, consider yourself VERY lucky. But if the engine was damaged from overheating, you're going to be looking at some major money -- more than likely another car -- so the $100 spent on the expansion tank repair will be just a drop in the bucket. Its a low gamble considering the stakes.

In all honesty, I'd say your engine is toast. Typically an engine can handle running in the red for about a minute before damage starts. But several minutes and several miles is another story. Even still, I would replace the tank and see what happens. The sun shines on a duck's ass every now and then.

Even the slighest needle movement past Normal Operating Temperature you should pull over and turn your car off. I would check your cylinder heads, they could be warped.

One of the problems is that our temp gauges are buffered, and do not reflect "real-time" status. i.e., they`re always lagging behind, so the actual coolant temp has probably been in the "danger zone" longer than you thought. This is why it`s critical to shut everything down ASAP. You can also turn your heater on full blast to help vent some of the excess heat to to the atmosphere....

I agree with Hallistran`s approach....try putting it back togethrer, and see what happens when you drive it. Good luck !

When you said the car stopped, did you mean that you finally decided to stop or that the engine stopped on its own? If its the former you may get lucky but if its the latter you have a very large paperweight under the hood. The I6 is a great engine but will not tolerate overheating.

With cylinder 4 at 25% leakdown, you are right at 135 psi compression. Tolerance for leakdown is about 10-12%. My educated guess is that the head is warped a couple of mills, and the threads in the block pulled out.

Originally Posted by TannerT

If you catch it right away you are usually safe. Aluminum does not like to get hot. If you drove 5 mikes in the red you are probably in trouble but who knows. Check it out, check oil and such. Wait for one of the pros to chime in here.

Sent from my PantechP9060 using Bimmer App

I drove way more than 5 miles with my E36 in the red. I think I had overheat incidences twice. Engine was still fine like 70k miles later.

Originally Posted by Chris90

I drove way more than 5 miles with my E36 in the red. I think I had overheat incidences twice. Engine was still fine like 70k miles later.

You were luckier than most, Chris....doing that is like playing Russian Roulette with half the chambers loaded....

Thank you all for your responses, I have decided to get the cracked tank fixed (around 500 bucks including thermostat) and see what happens. I want to try my luck, I will update you guys.
my biggest question is how bad are my leak-downs. I read in many forums that leak down in and around 20% is like little worn engine but still can run. any thing beyond 30 means real problem. I want to understand from that perspective.

Thanks
Kris

Originally Posted by Chris90

I drove way more than 5 miles with my E36 in the red. I think I had overheat incidences twice. Engine was still fine like 70k miles later.

When you had overheating issues, did you or your mechanic do any compression test or leak down test. Do you remember the results. Would appreciate if you could share that information.

Thanks

Ok..I have got the coolant tank done. I am yet to go see the car but the mechanic tells me that the engine is shaking, not sure what it means. Any thoughts.

Originally Posted by isitkittu

the mechanic tells me that the engine is shaking, not sure what it means. Any thoughts.

Could be any one (or combination of) a hundred different things....doesn`t your "mechanic" have a code scanner ?

Originally Posted by isitkittu

Ok..I have got the coolant tank done. I am yet to go see the car but the mechanic tells me that the engine is shaking, not sure what it means. Any thoughts.

If possible, make a short video and post it.

Originally Posted by Chris90

I drove way more than 5 miles with my E36 in the red. I think I had overheat incidences twice. Engine was still fine like 70k miles later.

Late to the party, but if you all recall some years ago a guy who contacted me via the web (don't remember how he got my name) and he lived in Chatanooga, TN and his daughter was in Bham at a wedding when her E46 overheated. She drove a good 10 minutes (according to her) with the car in the red. Her waterpump shaft snapped at 77k miles. I put it back together and fixed it but told her there was a VERY good chance the engine was nuked. Well, somehow (angels maybe ) her car ran fine and has been for some time.

This is the EXCEPTION though and not the rule!