30 replies to this topic

[treadman]

Has anyone come across this problem, the coolant is filling up the expansion chamber,meaning it leaves the radiator short of coolant,if i siphon of the the expansion chamber to the lower level ,the amount of coolant siphoned of tops up the radiator, surely the radiator should be full at all times,when the bikes out on the road the temperature gauge stays normal,only rising in traffic then lowering when on the move, its a bit of a mind bender, can anyone help me out . pm if you want.
Neil

[treadman]

oops didn,t mention the bike TDM900 , its got a brand new radiator cap bought mail order from fowlers,how does the coolant return,not by capilary action by any chance, whats wrong if the coolant doesn,t return.

[npunsey47]

Has anyone come across this problem, the coolant is filling up the expansion chamber,meaning it leaves the radiator short of coolant,if i siphon of the the expansion chamber to the lower level ,the amount of coolant siphoned of tops up the radiator, surely the radiator should be full at all times,when the bikes out on the road the temperature gauge stays normal,only rising in traffic then lowering when on the move, its a bit of a mind bender, can anyone help me out . pm if you want.
Neil

replace the rad cap that should do it ok

[ChrisG]

If it's not the rad cap, it could be a blown head gasket. I had a very similar problem last year, expansion tank was always full but the radiator was loosing water, replacement rad cap didn't fix it, new head gasket did. Gas was getting in to the coolant (but no oil in the coolant or coolant in the oil) forcing the coolant out in to the expansion tank, then when it cooled the gas in the radiator meant it kept its pressure and didn't suck coolant back from the expansion tank.

[treadman]

she,s only done 18000mls , i hope you are wrong , what sort of money are we talking about for a new head gasket to be fitted. gulp!

[ChrisG]

I did it myself, it's not actually too hard a job if you're reasonably mechanically minded, and a local bike shop just happened to have a 3VD head gasket sat on the shelf left over from a previous job that he sold me cheap. The time consuming bit is getting to it. Dunno about the 900 but on the Mk1 you need to remove the faring, tank, airbox, thermostat, radiator and carbs to get the rocker cover then the head off.

You can get the coolant tested to check for signs of engine gasses in it but I had a chat with the bloke who services my car and he said he's got one of the kits to do it but they're fairly unreliable, in the end I just decided it was going to be cheaper and easier for me to replace the head gasket and hope that fixed it than spend a fortune for Woking Yamaha to diagnose the problem.

Edited by ChrisG, 21 September 2008 - 04:40 pm.

[treadman]

Chris you are a braver man than me,i,ll be phoning the local Yam shop and getting it booked in, subject to a estimate that is,thanks for your help so far will keep you posted on developements.
Neil

[JamJar]

to be honest , i wouldnt worry about it , , all cooling systems find there own level , mine is exactly the same for a few weeks now i have been concerned that the level in the rad looks to be about two inches from the top so i top it up and go for a run only to find its just put it in the expansion tank , each time the level in the rad goes down to the same point and the bikes temperature hasnt gone up ,

if your realy concerned have a compression test on the engine and that will reveal all , i did and mine was well within the limits

[JamJar]

sat on the loo lastnight and it occured to me that on MK1's the radiator top hose (on the left) is only half way up the rad , never seen it before but it would exlain why the water settles low in the rad

[treadman]

i was thinking the same thing and wondering why the temperature gauge was stiil giving the usaual safe readings, but when the radiator cap is released and look into the radiator and see no coolant you must admit its a bit worrying, anyway its booked in for a compression test next tuesday, lets hope its ok.
Thanks for the assuring words, i may be overeacting i hopei,m wrong.
Thanks fellow TDM riders
Neil

[treadman]

Hello again fellow TDMers, just an update,my next door neighbour also has aTdm 06 whipped off the side panel,the tdm has been unused since sunday, removed the radiator cap and lo and behold a completely full radiator and the coolant bottle at the lower mark, therefore with my TDM being completely the opposite , does this mean there IS a problem .

confused
Neil

[JamJar]

well i hope not as mine is exactly the same , at the weekend went for a 20 mile ride both ragging and sat in traffic and it didnt even get hot enough for the fan to cut in which is normally above halfway on the guage , yet as you say , looks like no coolant in the rad and over the full mark on the filler bottle , , interesting too see how yours turns out at the garage

[JamJar]

sorry all but ignore all of my previous posts , checked my coolant today and its not returning back into the rad , started bike and watched it and a bubble appears in the expansion tank , looked further into it and the reason the temp guage shows normal is becasue its showing the air temperature in the thermostat housing as their is no water in it .

i think the leaking head gasket is causing a air lock ,

anyways I stripped the bike in my lunch hour and i am going to check the torque of the head bolts first but i think its going to need a new gasket at the end of the day , i feel like pants on a fat man at the moment and as usual its at a time when money cant be spent on bikes..

so who knows a good place to get pattern gaskets ????

[dapleb]

so who knows a good place to get pattern gaskets ????

Nope. I'd go orig for the head gasket. £30 ish?

[JamJar]

thats good i was expecting 50 ish , i can live with 30

[treadman]

Don,t be to hasty Jamjar.chorley Yam also suggested could be the thermostat,check all possibilitys 1st before divin in doing the head gasket, i know its a bit of a wait till tuesday,but i might have an anwser for you
Neil

[JamJar]

thanks tread , i did think about the thermostat but there is definately a (although small) amount of air coming out which i would have thought can only come from the cylinder. i cant get the gasket yet so i am going to do a compression test before and after i check the torque on the head bolts