I've had a coolant leak for some time now, thought it was the water pump, chaged that a few weeks back, didn't do it. I found it to be the intake manofold gasket (well, the o rings technically) so yesterday I replace the gasket and o rings. Seems to have solved my leak, but now it idles real rough. Uneven rpms, minor exhaust popping etc. My car has always idled super smooth with little or no exhaust popping, so I can't figure why it's doing this. Any ideas? Also every so often when I let my foot of the gas and continue moving I hear a slight whiste, almost like a vaccum leak of sorts. I'm gonna assume the problems are realted, how can I go about fixing this? Oh yea, the car is a 83 S with the original 12a in it, and I have the shutter valve plugged (has been for almost 2 years) any ideas would be great. thanks guys.

 

Sounds like the manifold gasket isn't making a good seal and you have a vac leak.

 

ditto, just a question, did you replace just the o-rings? or both orings and gasket?
im having the same rough idle, and i got a new gasket sitting here waiting for my lazy *** to get off the computer and put it on.

Carl.

 

gasket and o rings, both were almost unrecognizable they were so shitty. If I had a manifold gasket leak would it still have all the power though? Cause it pulls just as hard up to redline as it did several days ago before doing this. Thanks for the quick responses, I hope I can fix this easily.

 

hmm, one other thing I should mention is that its running a little hotter than normal, not too much but enough to concern me. Think it has anything to do with it? I didn't mention it earlier becasue its been in the 70's this weekend compared to the 40's/50's it has been, so that could part of it, also I only had a little bit of coolant, so most of it is water right now, I plan on putting coolant in once I get some this week. What do you guys think?

 

Yes, it will run normally above idle. Either you didnt get the mating surfaces clean enough, or maybe one of the orings slipped out of place, causing a gap, leading to a vacuum leak. Either way, its a vacuum leak at the manifold.

 

ok thanks guys. This sucks, nothing like having to do a job twice, oh well, at least its no hard. It all makes sense. Any tips for cleaning the gasket surfaces? I used a razor blade to scrape it pretty clean then fine sand paper, a few spots weren't perfectly clean but seemed smooth enough, guess not.

 

I say just get rid of the O-ring and get yourself two 22mm freeze plugs. You'll have a much cleaner time taking your intake off in the future, no more coolant running out when you take off the manifold.

 

hey sean...i was worried about this when i did my upper intake...sooo...what i did was use gasket remover and metal sand paper and smoothed out the surfaces, then cleaned up the dust, sprayed on lots of gasket sealer and applied the gasket...no leaks that i can tell

here's a pic of one end of the surface and trust me...it was a bitch of a gasket to get off...

 

I had the same problem. A tech at Mazda told me to take some carb cleaner and spray it close to different parts of the intake gasket you just changed. The RPMs should increase when you spray it near a leak because the carb cleaner will leak through and burn. A quick and easy way to find leaks.

My fix was to remove everything again and use some of the blue gasket sealer from Permatex. I think it's called RTV.

Have Fun!

 

Thanks. I did the carb cleaner check yesterday, its leaking pretty much everywhere around it. My boss (ASE master tech) said to take it back apart, clean it better and use some of that permatex tach spray like you said. The car is my daily driver, so its gotta wait till thursday night for that, hope it holds out till then.

 

set it on somthing that you know is flat and shine a flashlight behind it. maybe you warped it somehow. if it is, just throw it on a huge sanding belt.

Carl

 

damn carlrx7...i just checked out your site...i love your car man...c-l-e-e-e-e-a-n!

 

I wouldn't drive my car with a known vac leak as bad as the one you are describing - You're runnig a very lean condition and your car will run a lot hotter, potentially cooking o-rings and/or injector seals