1990 Mitsubishi Montero Engine smokes, slight oil loss, coo

MICHAELGOODRICH

MEMBER
1990 MITSUBISHI MONTERO
6 CYL
4WD
AUTOMATIC
178,000 MILES

The vehicle smokes when started, and at idle, not so much when driving. I am losing some oil, and have to add a little here and there. I was parked at idle on an incline and the vehicle temp gauge started going up, it only appears to do this on incline. The temp stays fine at level and when driving. No oil in coolant, or coolant in oil. I have had the head gasket and valves redone in the past and it seemed not long after that the vehicle started over heating again and had coolant pushed up in the coolant reserve tank. So I replaced radiator, radiator cap, thermostat and that seemed to fix the problem for a long while. But now the smoke, temp rise on incline, and small loss of oil. I broke engine down to replace water pump and am installing new fan clutch. Whats going on?

5 Replies

KHLOW2008

MECHANIC
41,815 POSTS

Hi michaelgoodrich,

Thank you for the donation.

The temperature rising on inclines could be due to air pocket trapped in cooling system.

Try bleeding the system with the heater turned to maximum and radiator cap off.

If the clutch fan is weak, it would not be able to cool sufficiently at idling.

The smoke should be due to oil burning and this is most commonly caused by the valve steam seals. Were these replaced when the head gaskets were replaced?

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Sunday, November 15th, 2009 AT 7:52 AM

MICHAELGOODRICH

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4 POSTS

I did in fact have the heads cleaned, refinished and valve stem seals replaced. As far as bleeding the air from the cooling system, I did try that. But I was informed that if you have a closed system the air would simply be expelled from the reserve tank, is this true?

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Sunday, November 15th, 2009 AT 8:31 AM

KHLOW2008

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This partly true.

If the air trapped is a little, they would be expelled. If the amount of air trapped is substantial, they would not be expelled as excessive amount can be compressed and would not be expelled.

Were the valve stem seals used of OEM standard?

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Sunday, November 15th, 2009 AT 12:11 PM

MICHAELGOODRICH

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4 POSTS

O.K. I did put vehicle on up hile incline & ran heater on high with radiator cao off, I guess we will see if that along with replacing water pump & fan clutch will fix over heat. As far as the O.E.M. Valve stem seals go, I took the heads to a shop recommended by the mitsubishi dealer, it does seem they did not last long. I am going to have the heads & valves done again, any recommendations? And thanks for your help

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Sunday, November 15th, 2009 AT 6:06 PM

KHLOW2008

MECHANIC
41,815 POSTS

When replacing valve stem seals, I do not need to take the heads off. I use regulated compressed air to pump into tne cylinders to keep the valves closed when removing the valve springs and replacing the valve seals.

You would need some specially fabricate tools for the job.
1. A connector to be screwed onto the plug holes for the compressed air.
2. A special leverage tool for compressing the valve springs. This item might be available at some tools outlets.

Maybe you can check around to see if any shops have the tools and performs such replacements. It would save a lot of headache, time and parts cost.