earckens Posted August 5, 2023 Report Share Posted August 5, 2023 (edited) The old ventilator missed 1 of 8 blades, doable to drive but I decided to replace it with a new ventilator. All well except I installed the ventilator the wrong way round, and too close to the radiator I found out after starting the engine. The ventilator blocked against the radiator, luckily not causing damage there. However after installing the ventilator correctly, and, making sure enough coolant is present, I started the engine. But a loud hissing sound ensued, it almost seems as something is binding, or (I hope not) the timing between crankshaft and camshaft is corrupted. Basically, starting the engine with startermotor and blocking the crankshaft (where the ventilator is attached) could this cause this hissing sound? Edited August 6, 2023 by earckens Quote Link to post Share on other sites
stillp Posted August 5, 2023 Report Share Posted August 5, 2023 Is the starter drive jammed, so the hissing sound is the engine turning the starter motor? Pete Quote Link to post Share on other sites
earckens Posted August 5, 2023 Author Report Share Posted August 5, 2023 No, the motor starts ok. The hissing sound start when cranking the engine and keeps going when the starter is released. What worries me is that this hissing sound also exits with the exhaust. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted August 5, 2023 Report Share Posted August 5, 2023 Disconnect or loosen the rubber drive belt. Does the sound go away? Quote Link to post Share on other sites
earckens Posted August 5, 2023 Author Report Share Posted August 5, 2023 12 minutes ago, BlueTR3A-5EKT said: Disconnect or loosen the rubber drive belt. Does the sound go away? Does the rubber drive belt only drive the dynamo and the waterpump? So it is ok to loosen that belt and check for this sound? Quote Link to post Share on other sites
MichaelH Posted August 5, 2023 Report Share Posted August 5, 2023 Correct the fan belt (rubber drive belt) only drives the dynamo and water pump- it wont change the drive from the crank to the cam shaft which is a chain behind the metal front of the engine. I had a similar noise with my engine : I found it by starting the engine then using a rubber hose. One close to my ear I could search across the engine to find the noise In my case it was leaking inlet manifolds which I solved by replacing the gasket I hope this helps Michael H Quote Link to post Share on other sites
jerrytr5 Posted August 5, 2023 Report Share Posted August 5, 2023 The 'ventilator' I am reading as the cooling fan would that be right? Is it possible the fan (ventilator) has slightly damaged the radiator enough to cause the hissing but not enough to create a large visible leak? Jerry Quote Link to post Share on other sites
earckens Posted August 6, 2023 Author Report Share Posted August 6, 2023 (edited) 13 hours ago, MichaelH said: Correct the fan belt (rubber drive belt) only drives the dynamo and water pump- it wont change the drive from the crank to the cam shaft which is a chain behind the metal front of the engine. I had a similar noise with my engine : I found it by starting the engine then using a rubber hose. One close to my ear I could search across the engine to find the noise In my case it was leaking inlet manifolds which I solved by replacing the gasket I hope this helps Michael H This morning I unmounted the waterpump/dynamo drivebelt, but the noise is still there. "Ventilator" indeed is the "cooling fan": is there a way I can change the thread title? EDIT= done. The damage caused to the radiator is just to the tiny heatdispatcher metallic threads between the radiator tubing. The radiator tubing is intact, no leaks. The manifold gasket: is this where the carburettors are connected to the engine? Edited August 6, 2023 by earckens clarification on thread title Quote Link to post Share on other sites
MichaelH Posted August 6, 2023 Report Share Posted August 6, 2023 Correct. usually there is a manifold gasket between the cylinder head and the manifold then again a gasket between the manifold and the carburettors. The idea that i was suggesting was to use the rubber tube to find the source of the noise. Like using a stethoscope to listen across areas of the engine to find the hissing noise. Michael H Quote Link to post Share on other sites
earckens Posted August 6, 2023 Author Report Share Posted August 6, 2023 3 hours ago, MichaelH said: Correct. usually there is a manifold gasket between the cylinder head and the manifold then again a gasket between the manifold and the carburettors. The idea that i was suggesting was to use the rubber tube to find the source of the noise. Like using a stethoscope to listen across areas of the engine to find the hissing noise. Michael H Good to know because I had no idea what you where refering to with the hose. Tomorrow I will unmount the cooling fan -to go back step by step in reverse order to what I had done-, and use the hose-stethoscope technique on the engine. Report tomorrow. Thanks for all this advice so far. Erik Quote Link to post Share on other sites
earckens Posted August 7, 2023 Author Report Share Posted August 7, 2023 Solved. The cooling fan blade ends had been striking the left rack-and-pinion chassis mounting bracket. Somehow the new fan must have slightly different dimensional specifications compared to the old one that was removed. Cutting off a small part of these blade ends and filing off the remaining excess once mounted, and no more noise. The hissing sound must have been a resonance with the part being struck on the car I guess. Anyway, thank you all for the response I received! Quote Link to post Share on other sites
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