Nubira 97 1.6 SX Repair Manual? Blown Headgasket

[Daniel]

Found a good piece of aluminum so i think ill make the thing tomorrow.

Heres a pic of the random spark plug that's blocking up a hose.

This is probably a heater hose. Connect both ends again with some pipe.

[Trey05Woo]

WOW amazing, wouldn't surprise me if thats the reason for the head gasket failure. They crippled water circulation by pluging both ends like that, I'm pretty sure car had to be running hot like that. Definetly get yourself a 5/8's adaptor, and join both hoses, or replace the heater core, it's fairly simple to replace...

[Daniel]

... or replace the heater core, it's fairly simple to replace...

Hey! Is that so simple? Don't you have to remove the whole dashboard?
Pls explain.

Daniel,

[Trey05Woo]

Technically yes but believe it or not the dashboards on these cars removes in about 30 min or so. The problem with Leganzas/Nubrias is the dash is delicate and can break or deform, unlike the Lanos's which is all plastic. But there is a way to remove the core without removing the entire dash though. It requires disassembling the glove box, removing the center console, and bending some brackets out the way so you can remove the hvac case cover. This method was taught to me by a former daewoo tech. The brackets are completely covered by the glove box so it is not a cosmetic issue, and it will not affect the performance, or damage the dash/core in any way. Plus they can be bent back into place. You also avoid having to discharge the ac this way...

[Daniel]

Alot of thanks for your post, Trey05Woo! Will save time & money. .

Daniel

[David_C]

Made the tool yesterday and got the timing belt off just before.
Now do I need to take the camshaft pulleys and the camshafts off? Or can i just leave them on there and take the head off in one piece?

[MMamdouh]

WOW amazing, wouldn't surprise me if thats the reason for the head gasket failure. They crippled water circulation by pluging both ends like that, I'm pretty sure car had to be running hot like that. Definetly get yourself a 5/8's adaptor, and join both hoses, or replace the heater core, it's fairly simple to replace...

blocking the heater lines will not affect the engine's cooling ability in any way or form

i have the heater bypassed on my woo and dad's woo since years and both cars are running fine... ambient tempts in here are some 36 to 38C in summer

it could be the time when the adapter broke the coolant got drained and the engine got over heated for a few minutes or so and that caused the gasket failure... those adapters are pron to failure and always replaced by aluminum ones here

MMamdouh

[Trey05Woo]

David the cam gears should come off to remove the head properly because the rear cover has two 10mm bolts which bolt it to the head. Though these can be reached with a universal socket, but much easier to remove with the cam gears off. The tensioner, and idler pulley must be removed to remove the head, and access to the tensioner bolts is also easier with the cams off.

And Mm id you plug the lines like in the picture or bypass them? I have a hard time believeing you will not experience hot spots in your cooling system if you plugged them like they are on davids car. You have a pipe that runs water directly from the cylinder head to the core, and the return line dumps this water right back to the lower hose/radiator. If you plug these lines you have dead water flowing right at the back of the head creating a hot spot. Just because you might not see a change in your temp readings inside, does not mean you are not creating a hot spot in the cooling system, which can deterioate the head gasket in that particular area.

Take a laser thermometer and point it at those hoses you have blocked off, (especially the feed of the head) and compare the readings, to the readings you see at the coolant gauge, you might be surprised...

[David_C]

Thanks for that info.

I finally got the head off today.

The two center head bolts were covered in oil and the head gasket is pretty rooted. The coolant galleys have a rusted color build up in them.

I removed the spark plug that was used to block the heater hose in the picture, the hose was full of black and rust colored sludge

What would be the best way to clean out all the rusted colored crap that is inside the coolant galleys?

What is the usual method for cleaning the head surface?

[Trey05Woo]

Well everyone is entitled to their own opinions but I think plugging that heater feed line is insane, and definitely contributed to the head gasket failure, so it doesn't surprise me you would find sludge in there. Could you post a pic of the head gasket? I would love to see what it looks like...
The rusting is normal, keep in mind the previous owner probably had it run hot/overheat and just kept adding pure water. I would replace all hoses, as well as the water pump and thermostat. As far as cleaning the mating surface goes, it would be wise to get your hands on an air compressor so you can blow all that stuff out of the block, and well as the residue from cleaning the mating surface. I use a die grinder with a super soft plastic cookie to clean the surface, but an electric drill with a soft cleaning wheel will work too, and 80 grit sand paper and elbow grease too. Just get all the old head gasket material off, leave a nice clean surface. You dont want to go crazy and get a polished finish or anything. I would advise you position each piston at TDC while you clean the respective bore to prevent material from falling into the cylinder and getting embedded in the walls. I would really recommend compressed air, but a vaccum cleaner works as well.

I would also check the radiator and make sure all that gunk and sludge is not built up inside most probably is. Leaving it full of degreaser and water overnight will clean out alot of trash.

Oh and the head bolts must be replaced. Forgot to mention that earlier. They are torque to yield and cannot be reused.

[David_C]

Hey guys,

I have just got back from overseas on a short working holiday.

I'm getting straight back into getting this thing all fixed.

New head gasket, head bolts and timing belt arrived today. I should have the head on and torqued up by tomorrow.

It looks like the left engine mount has to be undone to get the timing belt on, how is this done without buying the special brace tool thats in the manual?

I was thinking on just putting a hydraulic jack underneath to hold it up?

[turbo1600]

use a jack with a peice of wood under the sump, be carefull that you dont jack it up too much and dent the sump.

mark k

[turbo1600]

WOW amazing, wouldn't surprise me if thats the reason for the head gasket failure. They crippled water circulation by pluging both ends like that, I'm pretty sure car had to be running hot like that. Definetly get yourself a 5/8's adaptor, and join both hoses, or replace the heater core, it's fairly simple to replace...

it wouldnt do any damage would it ? it be just the same as if you had the heater controll on cold instead of hot.

mark k

[Daniel]

WOW amazing, wouldn't surprise me if thats the reason for the head gasket failure. They crippled water circulation by pluging both ends like that, I'm pretty sure car had to be running hot like that. Definetly get yourself a 5/8's adaptor, and join both hoses, or replace the heater core, it's fairly simple to replace...

it wouldnt do any damage would it ? it be just the same as if you had the heater controll on cold instead of hot.

mark k

Hi turbo1600,

It was a quite old post (Nov 09, 2009) but for clarity on such Daewoo there is no more tap to control heat. Instead of a tap it is a flap that obscures more or less the heater core air flow wherein always circulates the coolant. Blocking this coolant flow by plugging hoses may create a hot spot on the cylinder head. The best temporary solution before replacing the heater core is connecting the two pipes together.