Radiator exploded, should I replace anything else?

[JKuhn]

As the title says. Today I cleaned the MAF sensor on my '99 2.8, and while I took it for a drive (and boy, did that throttle body cleaner make a difference!) the radiator side tank (by the air intake ) exploded. Luckily I was cruising in 5th gear at about 60km/h, and it happened just before a bus stop, so I was able to pull off the road the moment it happened.

The engine is fine, so only the radiator seems to need replacement. Should I just put a new radiator in, or do some other stuff as well? The car just this week crossed the 180k km mark, with an unknown recent history. Also keep in mind my Mazda is not in perfect condition, so I'd prefer not to leave the BMW too long.

[colb]

At that mileage best to put a new radiator in, looks like the plastic degraded and gave up under pressure. whilst your in there best put a new water pump in and a new thermostat.

[MIKYZZ4]

It is usually recommended to refresh the entire cooling system, if at all possible.
Radiator,thermostat,waterpump,expansion tank, and all associated hoses.
This is due to all the plastic bits that make up the system, and failure due to age.

[bluptgm3]

…and BMW blue coolant for the sake of your head gasket.
T-stat generally gets 'cooked' when there is gross coolant loss. Replace water pump with BMW, Saleri OEM, Hepu, or Stewart brand pump. Wahler, or Mahle/Behr T-Stat.


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[JKuhn]

I'd prefer not to redo the entire system, since my wallet is already a bit of a problem at the moment. The thing is, my previous show car broke me financially, and on top of that I'm currently getting all sorts of initial expenses on the BMW (tyres, I still need to reweld the rear-end (I'm assuming that will do since I'm not planning to do hard driving), initial service, etc). So if I have to do the entire system the car will probably stand at least until the end of October (and considering that this is a BMW, probably longer), and I'd rather not have that (the Mazda also has stuff that are failing).

Regarding the thermostat, will that be a problem if I almost immediately (meaning within seconds of the radiator blowing up) shut the engine down? And is there a way to determine if the water pump is going to fail soon without taking it off? I'm also told that taking the water pump off will make it a lot more work, and I'm not sure if I'm ready to do that myself (or if I even have the right tools).

EDIT: Thanks for the heads-up about the coolant though.

[Remotion]

It is usually recommended to refresh the entire cooling system, if at all possible.
Radiator,thermostat,waterpump,expansion tank, and all associated hoses.
This is due to all the plastic bits that make up the system, and failure due to age.

How much does it cost to do all of this at once, for 2.8 z3?
Gross estimate would help, I am thinking that I should do that on timely manner rather than too late.

[JKuhn]

I can't say, but considering that it's a BMW it will probably be insanely expensive... Also, keep in mind that prices (especially labour) don't translate well across countries.


Oh, and I might be able to contact one of the previous owners, they might have info on when the pump was last done.

[Wertles]

Nobody prefers to spend money on a cooling system and nobody prefers to be stranded on the side of the road but it happens. As you can see, the plastic has failed from years of service and many heating and cooling cycles. Every bit of plastic in the cooling system looks like that so replace it now or replace it later. Your choice, but the later leaves you on the side of the road and ends up soaring you way more money in the long run. If you did research before you bought the car, you would realize the entire cooling system is a weakness of our cars and needs replaced every 100,000 KM or so. Do it once, do it right and don’t do it again. There are plenty of kits available from vendors that send you everything you need for a reasonable sum of money.

[bluptgm3]

In the states, it looks like a Z3 2.8l Valeo OEM replacement is ~$175 on eBay, with free shipping. WP from BMW ~$100, Saleri OEM slightly less, Hepu under $75, but your 1999 2.8L should have a OE formed/welded sheet metal impeller pump, so you should be safe there, watch for seal/bearing failure. The formed sheet metal pump was replacement for the initial (1992-~1998) failing OE plastic impeller pumps. BWM has gone back to a plastic/composite impeller pump as an OE replacement.
T-stat hopefully fails in the open position, so agin you can choose to let it ride, but watch the temp gauge, should always point high-noon. Hoses should be replaced if they show signs of excess softening.
Wholesale full system replacement is wise at the 80K - 100k miles on later cars.

E36 Behr radiators were reinforced at the inlet spud with thicker plastic that increased the life of the radiator from ~60K miles to the more normal ~100K miles.
That said a head gasket replacement will be close to $3K to repair.


ECS Tuning generally has a wide selection of parts and a good indicator of part cost.
Use www.realoem.com to determine part numbers using you build date (shown on drivers door sticker) or last seven of your VIN for exact part requirements.

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[JKuhn]

Noted.

As I said, I can't spend a lot on it now, so for the time being I'll have to only do what's needed. But when I do get the money together (and I'll try to do it sooner rather than later), I'll see to it that the rest also gets done. I was aware of the pump failing every 50k km or so, and also the flanges failing, but that's all I saw before I bought the car. At least there won't be any long distance shows for the rest of the year, so that will help. Also, the VANOS being fine also helps (the engine not pulling right was misdiagnosed as bad VANOS seals).

Speaking of which, wouldn't it be better then to have the flanges made form metal, and also a metal pump (if they're available)? At least over here we have Goldwagen, so I should be able to get most of the parts, if not all, there (unless I have some of them custom-made).

EDIT: I'm used to another site that gives new post notifications. bluptgm3: That's good to hear about the pump. I'll also have a look at the hoses, and keep an eye on the temp. But will the thermostat really fail that easily?

Anyway, I'm out for the night. I'm going away tomorrow, so I can't spend more time here. Thanks for the help so far, I'll be back later.

ANOTHER EDIT: Before I close the browser, the car was built Sept. '98, as a '99 model, if that makes a difference.

[LannVouivre]

Don't forget the plastic pipes under the intake manifold, if the 99 has them. Also get new intake boots, IACV grommet, gaskets, and vacuum hoses so when you pull the intake manifold you are prepared.

Also clean the threads of or replace the radiator fan switch before you install it or the Valeo radiator bung will detach and the switch will be a permanent part of the radiator.

Lastly, remove the clutch fan if your auxiliary fan is functioning properly. It's a bitch to install, a bitch to remove, and damned if it isn't a bitch when it explodes as well. The aux fan is adequate on its own, I suspect BMW kept on with the clutch fan just because they've always done it that way.

[bluptgm3]

The fan nut is left hand thread. A 32mm (?) bicycle head wrench works great, swing from left-to-right from the top. Paint anti-seize on the threads, and when reinstalling, resist tightening beyond just-set.


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[Vintage42]

... your 1999 2.8L should have a OE formed/welded sheet metal impeller pump... The formed sheet metal pump was replacement for the initial (1992-~1998) failing OE plastic impeller pumps. BWM has gone back to a plastic/composite impeller pump as an OE replacement...

When I replaced my pump I used a Saleri composite which is the OE replacement.
I was afraid to use a sheet metal pump.
http://www.m3forum.net/m3forum/showthread.php?t=338159

[bluptgm3]

When I replaced my pump I used a Saleri composite which is the OE replacement.
I was afraid to use a sheet metal pump.
http://www.m3forum.net/m3forum/showthread.php?t=338159

The BMW OE fix in ~1998, the factory replacement for the failing plastic impeller pump, was a welded stamped steel impeller pump. Perhaps Hepu?


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[328 Power 04]

The later composite pump from BMW is quite good. Very easy on the bearings and stronger than the original brown plastic ones which crumbled to small pieces after 60-70k miles.

Never tried the cast impeller ones.

[JKuhn]

Don't forget the plastic pipes under the intake manifold, if the 99 has them. Also get new intake boots, IACV grommet, gaskets, and vacuum hoses so when you pull the intake manifold you are prepared.

Also clean the threads of or replace the radiator fan switch before you install it or the Valeo radiator bung will detach and the switch will be a permanent part of the radiator.

Lastly, remove the clutch fan if your auxiliary fan is functioning properly. It's a bitch to install, a bitch to remove, and damned if it isn't a bitch when it explodes as well. The aux fan is adequate on its own, I suspect BMW kept on with the clutch fan just because they've always done it that way.

Please don't even mention that...

My aunt had the enigne in her Kia K2700 replaced with an import engine, then the fan clutch (probably damaged by the importers) broke in the middle of nowhere (so she kept driving). Then she had the engine replaced (again), then one of the fan blades broke off. At least this time she stopped, and saved the engine.

[MRFAST]

Nobody prefers to spend money on a cooling system and nobody prefers to be stranded on the side of the road but it happens. As you can see, the plastic has failed from years of service and many hearing and cooling cycles. Every bit of plastic in the cooling system looks like that so replace it now or replace it later. Your choice, but the later leaves you on the side of the road and ends up soaring you way more money in the long run.

This

If other parts have not been replaced previously you will be experiencing another failure. Soon. This was the weakest point in the system that day.

[s8ilver]

As you can see, the plastic has failed from years of service and many hearing and cooling cycles.

What's that you say? I didn't heat you

[ZGator]

sorry, could not resist..

fan delete +1, if you need to be cheap now, and need to get back in there..

[Mr Bingley]

Bottom line OP, when it comes to a complete coolant dump on the road, you got lucky once--don't count on that luck again going forward.

[JKuhn]

I'll save a bit and then replace the rest ASAP. Like I said, I'll have to cheap out for the moment though. But, at least I won't have long distance trips for the time being.

[JKuhn]

Update:

The radiator exploded because the thermostat broke apart, blocking the flow of coolant. A new thermostat is in, the waterpump is not replaced (can't afford it, but we did inspect the old pump), and the radiator is repaired (new tank). Now to buy a new belt (the old one is very loose), new bottom hose, and then I need to hope for the best...

[bluptgm3]

If belt is loose you may have to replace the tensioner, what type do you have? Hydraulic-spring/clock-spring.
If hydraulic-spring then I recommend having a look at the pivot bearing. Mine seized, brinelling the pivot shaft.


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[rf900rkw]

Update:

The radiator exploded because the thermostat broke apart, blocking the flow of coolant. A new thermostat is in, the waterpump is not replaced (can't afford it, but we did inspect the old pump), and the radiator is repaired (new tank). Now to buy a new belt (the old one is very loose), new bottom hose, and then I need to hope for the best...

I disagree. The radiator exploded because the system pressure exceeded what the antique plastic could handle. This excess pressure came from one of two sources. It was either overfilled, or it overheated. The broken thermostat could have been the root cause of an overheat, but it in itself didn't not grenade the radiator tank.


Speaking of grenade, this is the first time I've ever seen one glued back together so it can blow up again. You replaced ONE tank?

[JKuhn]

That's what the radiator shop did. They said it was not an age-related failure, but excessive pressure. Also keep in mind my budget is already out the window, and I'm not even done buying parts that clearly need to be replaced. And yes, I meant that the broken thermostat caused an overheat, which caused the radiator to explode. So the thermostat essentially caused the explosion.

Regarding the belt: I'm not sure what you meant. I do know the local old car club member who helped me said to replace the belt. Basically the tensioner reaches its limit, without pulling the belt tight enough. And speaking of which, I haven't had a proper look yet (it was getting late), but how does the aircon belt come off (so I can replace the main belt)?