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96 intake manifold leak?


winterset

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I hope I find you all doing well.....

My car never had any work done and i am the original owner 

new oem rad, hoses, oem surge tank back in 2015 as preventative measure

coolant has been changed every 3-4 years with tablets in the lower hose

been using the car only a little in the summer and fall months, and dry docked for the winters

i had no problems this summer, but it did seem shakey when i first started it, and in 2020 i might have driven less that 1000 miles

yesterday the “low coolant message” came on for the first time ever.

today i spent the day starting it, it gets to 196 degrees like it always does, then i let it run, shut it down, and let it cool. rince repeat about 6 times.

i might smell coolant in the exhaust, and it seems whiter than i recall. no visible leaks anywhere

there is no pressure in the surge tank, and i actually have a second surge tank which is a small plastic bottle to collect the overflow from the surge tank hose on the cap - and that has been there for many years. it has been empty, and my surge tank was topped off

today after all the starts, the surge tank dropped about 1”

i suspect my intake manifold gaskets are leaking coolant into the intake?  does this sound feasible? how tough is this job if it is?  what do you all think?

sorry i have been away for a long time, and i come back with a problem!!

i just did my yearly oil change with diesel 15w40 the other day too. - the old oil was clean

 

 

thanks.

 

 

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Welcome back

Intake is dry on these. No fluids pass through.

Coolant does pass through the throttle body but I have yet to have one fail.

When you say shakey on startup I assume you mean it feels like a stumble.

What you describe is exactly what my 96 did when the head issue started to occur.

If I drove it daily it did not miss on startup.

If I drove it occasionally it would miss on the cold start. The miss is caused because of the coolant leaking into the cylinder(s).

Once the coolant is out of the cylinder(s) it runs fine. If this is what yours is doing I highly suspect you are in the beginning stages of headgasket failure. I babied mine for 2 years by adding Bars leak to the lower hose. It would be good for about 6 months, then would start to Cold start miss.

Mine never ran hot until the day it eventually blew. Then it blew exhaust into the coolant and boiled it over.

Car had over 200k, never did me wrong. Was not worth fixing.

If yours is in good shape I highly recommend repairing it. I love mine and have been incredibly reliable

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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If pipes are rusty then externally. Never had one fail internally but my guess would be into the throat of the intake. Doubt it though.

You could take the tube off the TB and put a paper towel in there overnight.

If you want to look for a external leak check below easy to miss spots.

Check radiator side tanks, especially the passenger side. Look for swelling and cracking.

Check the cap and neck. Have seen the seal missing or bad under the cap.

I did not bring that up right away given your list in the original post.

Just out of curiosity did you used to deal with W-Bodies?

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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