Toyota Previa 1993 Smokey Exhaust

[gjr5088]

Hi there

I've been reading your great posts on this forum, especially about head gasket failures and how to repair
My 150,000 mile 1994 2.4L van smokes badly on start up , but once the water temp gauge levels, the smoking disappears
It is consuming coolant. I drive the van twice a week, for 1/2 mile to keep everything running ok - is this advisable??

Could I ask if you would be willing to watch a very short video to advise me what I should do next? [I can't seem to upload a video :-( ]
I live in United Kingdom near Liverpool. Unfortunately Previa specialists are very thin on the ground :-/

Very much appreciated
Kind regards
Gary Rimmer

[John Kaufmann]

It certainly looks like a head gasket leak on one of the cylinders, and the coolant loss seems to confirm it. Do you also see evidence of water in the oil?

I don't think it's a good idea to run it once a week until the head gasket is replaced, especially if there is water in the oil.

[gjr5088]

Hi there
Thank you very much indeed to take the time to read and reply to my message - much appreciated
I've not been able to investigate the water in the oil so far, but I will take a look.
Could I ask if it is normal that the engine, once warmed up, stops blowing smoke and appears to run normally once the engine is at normal operating temp? Initially my local Toyota garage suspected failure of the valve stem seals.
All the best
Gary

[John Kaufmann]

... I've not been able to investigate the water in the oil so far, but I will take a look. ...

Water will make the oil more of a milky (even foamy) light brown. That said, you can have a head gasket leak without getting water in the oil.

... Could I ask if it is normal that the engine, once warmed up, stops blowing smoke and appears to run normally once the engine is at normal operating temp? Initially my local Toyota garage suspected failure of the valve stem seals. ...

Worn valve stem seals let oil leak into the cylinders when the engine is not in use, resulting in a puff of blue smoke when you start up. That small amount of oil usually clears pretty quickly, regardless of temperature -- and after that burn-off, the small amount of oil that may leak is not enough to cause visible smoke. [I had to replace mine once.] It is a nuisance, to be fixed as soon as practical, but does not threaten the engine.

The head gasket leak is more temperature-dependent, as the warming aluminum head squeezes down on the block, so the cloud typically is whiter and lasts longer -- though a bad head leak can continue even at high temperature.

[Previologist]

Could I ask if it is normal that the engine, once warmed up, stops blowing smoke and appears to run normally once the engine is at normal operating temp?

Yes. it is normal for a leaky head gasket to behave that way.

No you shouldn't drive it, because you risk more serious damage. Not sure if there is an equivalent in the UK but in the US you can get a pretty cheap kit that will detect exhaust gas in your coolant and confirm the leak. https://www.harborfreight.com/combus...tor-64814.html

But based on your pictures I would say you definitely have a head gasket leak. While coolant in the oil will also confirm it, in my experience with a couple of Previa head gasket leaks I got oil in the coolant but not the reverse. In the early stages you might not see either one.

[timsrv]

Another clue would be the smell of the exhaust. If it's coolant it will smell like antifreeze.......and yes, like the others have said, smoking while cold then clearing up after warm-up is fairly typical of a blown head gasket on these.

There are "stop leak" products out there that can fix, but I'm not crazy about these as they can create other problems. If you plan on fixing it right, then don't use a stop leak product. If you're not going to fix it and just want some more miles, then they can be useful. I have love/hate feelings about these products. The love comes when it saves your bacon by allowing you to put off fixing the right way. The hate part is when you do finally fix it and the coolant system is contaminated (that can cause radiator problems, water pump issues and/or cause the T-stat to stick). A couple of years after I sold my Previa to a friend (about 10 years ago) it blew the head gasket @ ~ 200k miles. He put "Bars Leak" in it and that stopped the leak. He has considered that van to be on it's last legs for the last 8 years but the gasket is still holding and he's put ~80k miles on it since then (so far no other ill effects have presented themselves). Your mileage may vary. Tim

[gjr5088]

Hi Tim
Thanks very much for taking the time to reply
I have the Previa booked in for assessment at a local garage at the end of July, recommended by my Toyota garage. The owner/technician comes hight recommended, so I would like to direct him to this website, should he need to benefit from the detailed threads that many users (and yourself) have generously posted. Thanks for suggesting the leak-fix products, but I'd prefer to go down the full repair route! I'm just hoping that the necessary parts are somewhat easy to source [fingers crossed]

I'll keep the group updated, and extend my thanks for the support received so far :-)

All the best
Gary

[gjr5088]

Hi Everyone

By way of an update. I am a couple of weeks away from getting my Previa transported to the garage who has agreed to attempt the head gasket repair.

My local Toyota main dealer has ordered a replacement head gasket. It was showing in stock at Toyota (Japan, I suppose), so fingers crossed it should arrive in a few weeks.

Unfortunately, the head gasket repair kit is showing as obsolete and unavailable to order.

Does anyone have any experience of an online source for repair kit T04112-76071 please?

Many thanks to this important group!!

All the best
Gary

[John Kaufmann]

. . . Does anyone have any experience of an online source for repair kit T04112-76071 please? . . .

I presume you know of ToyotaPartsDeal?

[Previologist]

I've been trying to figure out what exactly is in a 'valve grind kit" but haven't had any luck. Is it really necessary for a head gasket job?