1998 Previa Core Plug Replacement

[RichardH]

[edit]Actually, not sure it IS a 98 - P reg old shape 2.4 GLS, anyway.

Looks like the dreaded problem has struck.

Our local mechanic has had a good look with the seats out, and while he can't see EXACTLY where the water's coming from, it doesn't seem to be the head gasket - he's also checked for hydrocarbons in the radiator fluid, and all is clear. So it seems that it's a core plug that's failed.

He's never done one before, but another mechanic he knows has quoted approx £800 to do it. With the car worth £1500 or so, it's bordering on the "not worth it". I doubt I have the time or facilities to do it, but is there any chance of being able to access the core plug without dropping the engine out? Maybe by cutting a section of the floor out?

Any advice?

[propnut]

[edit]Actually, not sure it IS a 98 - P reg old shape 2.4 GLS, anyway.

Looks like the dreaded problem has struck.

Our local mechanic has had a good look with the seats out, and while he can't see EXACTLY where the water's coming from, it doesn't seem to be the head gasket - he's also checked for hydrocarbons in the radiator fluid, and all is clear. So it seems that it's a core plug that's failed.

He's never done one before, but another mechanic he knows has quoted approx £800 to do it. With the car worth £1500 or so, it's bordering on the "not worth it". I doubt I have the time or facilities to do it, but is there any chance of being able to access the core plug without dropping the engine out? Maybe by cutting a section of the floor out?

Any advice?

The core plugs do go but the water pump is a common problem. Also can you actually see water coming out or are you just noticing a loss of water from the header tank. If the latter try changing the rad cap. One other thing worth checking is the heater matrix. This corrodes big time especially if some idiot has been putting tap water in the system. Try nt using the heater and see if you still lose water.

[RichardH]

The core plugs do go but the water pump is a common problem. Also can you actually see water coming out or are you just noticing a loss of water from the header tank. If the latter try changing the rad cap. One other thing worth checking is the heater matrix. This corrodes big time especially if some idiot has been putting tap water in the system. Try nt using the heater and see if you still lose water.

Thanks for the comments. He's had the front seats out and the inspection panels up, and can see close enough that he knows the water's coming from the casing somewhere, but not quite far enough round a corner to see it coming out.

[propnut]

The core plugs do go but the water pump is a common problem. Also can you actually see water coming out or are you just noticing a loss of water from the header tank. If the latter try changing the rad cap. One other thing worth checking is the heater matrix. This corrodes big time especially if some idiot has been putting tap water in the system. Try nt using the heater and see if you still lose water.

Thanks for the comments. He's had the front seats out and the inspection panels up, and can see close enough that he knows the water's coming from the casing somewhere, but not quite far enough round a corner to see it coming out.

By removing the front engine mounts and carefully lowering the engine on an hydraulic jack making 100% sure no wires or pipes are stressed, you mechanic should be able to gain sufficient clearance between the body and top of the motor to take a look using a torch. Be advised there are two water pipes that flow from the water pump to the throttle body and EGR and then return along the same path that run on top of the engine. Could be that these are leaking. They are quite hard to see but if the engine is placed on a ramp or lift the pipes can be traced from just above the secondary shaft. It is still possible that although the leak seems to be coming from the block that it is actually coming from the head gasket. Water has something called capillary action which means where you see it is not necessarily where it is coming from.

[RichardH]

Thanks Propnut. Will pass that suggestion on.

[RichardH]

Well, a result! I got in touch with Bob the Estima specialist a while ago, and he said he'd pop by when he was up my way - which he did this afternoon. With the aid of his pressure test kit and some cunning mirrors, we managed to see exactly where it's coming from - and yes, it's the top front core plug.