OVERHEATING, ENGINE MISSING SOLVED!
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Posts like a V-Tak
Joined: Mar 2004
Posts: 55
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From: CALEXICO, CA 92231

Hello there!
It'* been a while since I posted due to internet connection problems. I have a 93 ssei that was a salvaged vehicle that was overheating and rough starting. As per your suggestion I replaced radiator, hoses, O2 sensor,180 thermostat, re-set the computer, etc. All to no avail. Now I write to tell you what solved the problem so anyone having these simptoms can look at this and see if may aliviate their problems.
Ended up being a combination of two things:
1) A slowly desintegrating harmonic balancer
2) A rear exhaust manifold with a hole in it.
Replaced the harmonic balancer and cleaned the sensor. Also took out the exhaust manifold (rear) and welded the hole.
Problem solved ....so far
Any comments would be appreciated.
It'* been a while since I posted due to internet connection problems. I have a 93 ssei that was a salvaged vehicle that was overheating and rough starting. As per your suggestion I replaced radiator, hoses, O2 sensor,180 thermostat, re-set the computer, etc. All to no avail. Now I write to tell you what solved the problem so anyone having these simptoms can look at this and see if may aliviate their problems.
Ended up being a combination of two things:
1) A slowly desintegrating harmonic balancer
2) A rear exhaust manifold with a hole in it.
Replaced the harmonic balancer and cleaned the sensor. Also took out the exhaust manifold (rear) and welded the hole.
Problem solved ....so far
Any comments would be appreciated.
how big of a hole in the exhaust manifold? thats the first time ive heard of that problem on a Bonneville, but hey im glad you got it up and running, just dont go oppressing us naturally aspirated folks with your fancy shmancy supercharger...
I am in no way saying you are wrong...
The harmonic balencer was what was causing the misfire, right?
But how does a hole in the exhaust manifold cause overheating? Do the exhaust gasses in the engine bay really heat things up more than the manifolds getting hot themselves?
Just looking for education
The harmonic balencer was what was causing the misfire, right?
But how does a hole in the exhaust manifold cause overheating? Do the exhaust gasses in the engine bay really heat things up more than the manifolds getting hot themselves?
Just looking for education
Originally Posted by Logan
I am in no way saying you are wrong...
The harmonic balencer was what was causing the misfire, right?
But how does a hole in the exhaust manifold cause overheating? Do the exhaust gasses in the engine bay really heat things up more than the manifolds getting hot themselves?
Just looking for education
The harmonic balencer was what was causing the misfire, right?
But how does a hole in the exhaust manifold cause overheating? Do the exhaust gasses in the engine bay really heat things up more than the manifolds getting hot themselves?
Just looking for education

The exhaust leak can cause elevated temps because the motor will run w/less restriction depending on the size of the hole. On that note...my FEM was cracked when I got the car in about 3 places.
Thread Starter
Member
Posts like a V-Tak
Joined: Mar 2004
Posts: 55
Likes: 0
From: CALEXICO, CA 92231

Wel... As far as I understand it, it was a conbination of things:
The hole in the exhaust manifold (unknown size, sorry) was enough to throw the O2 sensor off. Also, it seems the harmonic balancer desintegration affected the sensor either by moving it out of position or by making it dirty. anyway, when the harmonic balancer was replaced, the sensor was removed, cleaned and re-installed.
It used to give me 160 miles per tank on regular driving conditions. Let'* see what it does now.
I'll keep you posted.
Ah! regarding the hole size... I didn't actually see it, but it was big enough that you could distinctly hear the pistons firing. Now it'* all quiet.
The hole in the exhaust manifold (unknown size, sorry) was enough to throw the O2 sensor off. Also, it seems the harmonic balancer desintegration affected the sensor either by moving it out of position or by making it dirty. anyway, when the harmonic balancer was replaced, the sensor was removed, cleaned and re-installed.
It used to give me 160 miles per tank on regular driving conditions. Let'* see what it does now.
I'll keep you posted.
Ah! regarding the hole size... I didn't actually see it, but it was big enough that you could distinctly hear the pistons firing. Now it'* all quiet.
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