Oh boy, leaking 750 heads after a couple overheats

**xboss** · 05-16-2017, 05:19 PM

Hey all,

My 750 has been drinking coolant and when I open the expansion tank I can smell exhaust and gas! Awesome eh?

No water in the oil yet so It's going to be redneck repair time. I am doing the blue Devil treatment (the full harder way) tonight. Wish me luck. Feel free to give opinion either way.

**ebida3** · 05-16-2017, 05:22 PM

Short term to sell it. Nothing can restore a bad gasket. A slight crack maybe but then it gets everywhere including heater core and radiator.
Good luck!

I spend thousands on my BMW the rest I pissed away.

**ebida3** · 05-16-2017, 05:22 PM

Originally Posted by ebida3

Short term to sell it. Nothing can restore a bad gasket. A slight crack in the head maybe but then it gets everywhere including heater core and radiator.
Good luck!

I spend thousands on my BMW the rest I pissed away.

I spend thousands on my BMW the rest I pissed away.

**xboss** · 05-16-2017, 07:06 PM

It's just my beater daily learning beginner 750. I just want to keep it alive for a while. I plan on doing the heads myself eventually but that will be after we move and get a second car. Eventually I hope to grab an Alpina from Europe and daily drive that bad boy next.

**XAlt** · 05-16-2017, 07:15 PM

Moroso ceramic and bypass the heater core.

**NordmanMg** · 05-18-2017, 08:59 AM

Originally Posted by ebida3

I spend thousands on my BMW the rest I pissed away.

Why you post this everywhere two-three times at a time?

**ebida3** · 05-18-2017, 09:03 AM

It's a signature. You set it up in settings.

I spend thousands on my BMW the rest I pissed away.

**4liter** · 05-18-2017, 05:38 PM

Try Blue Devil pour n go...worked for me...

**xboss** · 05-19-2017, 01:01 AM

Fingers crossed. I think it's not leaking now but I need a few more days to see. I think I'm running on 11, I bet a plug got fouled by the leak.

**XAlt** · 05-19-2017, 10:51 AM

Originally Posted by xboss

Fingers crossed. I think it's not leaking now but I need a few more days to see. I think I'm running on 11, I bet a plug got fouled by the leak.

Good news. As soon as you've confirmed it's not drinking anything flush it out, of all the head sealers, Blue Devil tends to get the worst reputation for clogging because of it being left in the system.

Pull the thermostat, engine drain bolts, heater core, everything.

**xboss** · 05-19-2017, 02:58 PM

Originally Posted by XAlt

Good news. As soon as you've confirmed it's not drinking anything flush it out, of all the head sealers, Blue Devil tends to get the worst reputation for clogging because of it being left in the system.

Pull the thermostat, engine drain bolts, heater core, everything.

Will do, I think I will bypass the heater core for the Summer. You guys are awesome with the tips. It did not occur to me that my core was at risk. I just checked the system again today. Revved the engine way up while watching for bubbles in the expansion tank and there were none. I still smell fuel but I'm sure the hoses are stained with fuel pretty good and I have not flushed it yet. It's def running on 11 or maybe even 10 due to fouled plugs so they are next.

If it holds up I'm going to drive a 1500 mile round trip this August to be in the totality of the eclipse on the 21st. I told my wife that you just have to believe and it will work

I never give up on cars, the intakes and valve covers need work anyway. It's right up my alley as just a big labor job. Just need some time before it happens.

**ebida3** · 05-20-2017, 07:21 PM

You understand this may not be a permanent fix? The fibers and resin that make up these compounds deteriorate in time under pressure.
I hope bought alot of time anyway. Good luck!

I spend thousands on my BMW the rest I pissed away.

**XAlt** · 05-20-2017, 08:43 PM

Originally Posted by ebida3

You understand this may not be a permanent fix? The fibers and resin that make up these compounds deteriorate in time under pressure.
I hope bought alot of time anyway. Good luck!

I spend thousands on my BMW the rest I pissed away.

When in doubt, add more.

**ebida3** · 05-20-2017, 10:23 PM

😁

I spend thousands on my BMW the rest I pissed away.

**xboss** · 05-21-2017, 02:01 AM

200 miles since the blue devil and I have not lost any coolant yet.

**xboss** · 05-21-2017, 04:15 PM

Be fun to do the heads. Just one big step past the valve covers eh?

Couple lock tools and send heads to a shop for rebuild. What does that run these days?

The rest is what $500 in seals from the heads to the maf?

**4liter** · 05-21-2017, 08:09 PM

Originally Posted by xboss

200 miles since the blue devil and I have not lost any coolant yet.

Pour N Go works

**xboss** · 05-22-2017, 12:43 AM

Originally Posted by 4liter

Pour N Go works

I did the bigger more expensive bottle. You have to flush and remove thermostat. I may end up flushing it again and tossing in the pour and go next because even though I have not lost coolant I think I'm still getting tiny little exhaust bubbles in the system.

**4liter** · 05-22-2017, 09:16 AM

Originally Posted by xboss

I did the bigger more expensive bottle. You have to flush and remove thermostat. I may end up flushing it again and tossing in the pour and go next because even though I have not lost coolant I think I'm still getting tiny little exhaust bubbles in the system.

Hmmm OK. Let us know how it turns out.

**masu3701** · 05-22-2017, 01:57 PM

Originally Posted by xboss

I did the bigger more expensive bottle. You have to flush and remove thermostat. I may end up flushing it again and tossing in the pour and go next because even though I have not lost coolant I think I'm still getting tiny little exhaust bubbles in the system.

That seal stuff will not work long term. I had a blown head gasket, and did try that stuff. Worked for a short time then had to replace engine. Got a used engine with 110k for $700
That stuff did clog things up. I have been flushing my cooling system to remove that junk and its taking forever to get all out.

So anyways, that stuff will not seal your head gasket. if you and when you will remove the valve covers, you will find loose and broken head bolts.
You either have to rebuild the engine or get a used one. I did start rebuilding mine, then had broken bolts in the block, stripped out, so I decided to not waste my 400$ getting the heads to be machines, and went and got used engine.

**xboss** · 05-22-2017, 04:38 PM

Originally Posted by masu3701

That seal stuff will not work long term. I had a blown head gasket, and did try that stuff. Worked for a short time then had to replace engine. Got a used engine with 110k for $700
That stuff did clog things up. I have been flushing my cooling system to remove that junk and its taking forever to get all out.

So anyways, that stuff will not seal your head gasket. if you and when you will remove the valve covers, you will find loose and broken head bolts.
You either have to rebuild the engine or get a used one. I did start rebuilding mine, then had broken bolts in the block, stripped out, so I decided to not waste my 400$ getting the heads to be machines, and went and got used engine.

I'm def rebuilding from the top up. A used engine will still have possible broken bolts as well. I know it's not going to last forever. I just want to go a few thousand miles. Cooling system is no big since it will all be replaced on the head job. Even the heater core will get replaced once I remove the stack to put new carpet in but that is at least a year away.

**masu3701** · 05-27-2017, 09:32 AM

Originally Posted by xboss

I'm def rebuilding from the top up. A used engine will still have possible broken bolts as well. I know it's not going to last forever. I just want to go a few thousand miles. Cooling system is no big since it will all be replaced on the head job. Even the heater core will get replaced once I remove the stack to put new carpet in but that is at least a year away.

well whats the point of rebuilding the top if the bottom wont be touched? YOu will have a strong top and a weak bottom block. It would make sense to rebuild the entire motor from the bottom
to the top.
And you should stop using that stop leak junk if you planing on rebuilding the engine.

**xboss** · 05-27-2017, 03:49 PM

Originally Posted by masu3701

well whats the point of rebuilding the top if the bottom wont be touched? YOu will have a strong top and a weak bottom block. It would make sense to rebuild the entire motor from the bottom
to the top.
And you should stop using that stop leak junk if you planing on rebuilding the engine.

Because I can rebuild the top no problem without pulling the engine. I'm just replacing all the seals from the heads up and everything above the heads is due anyway. It's still going to run like new and the bottom end should go much more than 200K. Car runs almost like new right now on a blown head gasket and 20 year old intake seals.

**xboss** · 05-27-2017, 04:15 PM

A rare part set that is selling for less than it used to. I guess nobody is doing the heads on blown 750's and just scrapping the car because you can get the $800 full kit for $300 now. Nice savings, now I just need to line up a shop to check out the heads and maybe this will get done by the end of Summer! Whats it run these days to have a shop work up a pair of heads?

http://www.ebay.com/itm/152560747038...%3AMEBIDX%3AIT

600 miles of daily driving since the blue devil. No loss of coolant that I can tell but I have been flushing it since. One last flush and I will get the thermostat back in and keep an eye on it. Still seems to be running on 11 but I have yet to look for the fouled plug...

**masu3701** · 05-28-2017, 07:34 AM

Originally Posted by xboss

A rare part set that is selling for less than it used to. I guess nobody is doing the heads on blown 750's and just scrapping the car because you can get the $800 full kit for $300 now. Nice savings, now I just need to line up a shop to check out the heads and maybe this will get done by the end of Summer! Whats it run these days to have a shop work up a pair of heads?

http://www.ebay.com/itm/152560747038...%3AMEBIDX%3AIT

600 miles of daily driving since the blue devil. No loss of coolant that I can tell but I have been flushing it since. One last flush and I will get the thermostat back in and keep an eye on it. Still seems to be running on 11 but I have yet to look for the fouled plug...

A shop would charge you around 3k. Its a job you can do if you have patience. I did got to remove the heads, then I decided to go the used engine route because I was having
very hard drive extracting the broken bolts. I had to get both the short and long block to get machine, and that was going to be around $2500-3000, SO I took the risk to go with a $700 used engine that had only 110k on it.

Installed it slowly, then was amazed how smooth the engine ran on first start.

IF not overheated, these engine are bullet proof. Cant kill them.

PM if you have questions while stripping it. Good luck