gt 40 cooling issue |
Post Reply | Page <12 |
Author | |
MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3736 |
Post Options
Thanks(0)
|
Take the thermostat out and test with no thermostat.
Sounds like restriction for sure. It the restriction is not in the thermostat start flushing. Maybe back flush the hoses and block, see what you get out of it. Could be a large chunk of a previously failed impeller coming back to haunt you. |
|
MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3736 |
Post Options
Thanks(0)
|
If none of the above solves your heating issue the engine water pump may be suspect. I have seen the impeller on some pumps rust away till it is ineffective and I have seen the impeller lose its clamp on the shaft and free spin rather than pump water. Rare and the last thing I would check but possible.
|
|
Hollywood
Moderator Group Joined: February-04-2004 Location: Twin Lakes, WI Status: Offline Points: 13514 |
Post Options
Thanks(0)
|
A blocked thermostat would give you cool risers.
Everyone wants to change thermostats but they rarely go bad. Like you said though, you can test it and also run without. |
|
wheels06
Newbie Joined: June-16-2008 Location: United States Status: Offline Points: 10 |
Post Options
Thanks(0)
|
Yes it did, that was why i changed it last year. I was hoping it solved the issue.
|
|
wheels06
Newbie Joined: June-16-2008 Location: United States Status: Offline Points: 10 |
Post Options
Thanks(0)
|
my apologies, my previous post was to the question of whether this issue existed before I replaced the impeller last yr. I just took the water pump off and noticed something. There was a post earlier, "the set screw is the key"...what do you mean by that? Mine is facing towards the engine. Is that correct? I have a Sherwood. Looking into the pump the impeller seems to be fine. I'll be checking hoses next. This is very frustrating given the weekend coming up.
|
|
Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
Post Options
Thanks(0)
|
John,
There's three different overheating at idle boats going concurrently in this thread, so it's easy to lose track. The set screw indicates which way the pump is facing. Per Hollywood, in is correct for a Left Hand Standard (Most GT-40s are) engine. Also, you'd be overheating at every rpm if it was faced wrong. 1.) Yours if fine anywhere but idle, right? 2.) Was there anything changed etc. before the overheat? 3.) If yours is getting hot at idle, 190ish, are the exhaust manifolds too hot to put your hands on, or is this just a gauge indicated overheat? 4.) You replaced the impeller: A.) Did you correctly position the thin o-ring B.) Did the kit come with a paper gasket and if so did you put it in (shouldn't reallymatter, but just wondering C.) Did you use a PCM or Sherwood impeller or an off-brand? 5.) Do you have a quick flush kit installed anywhere 6.) Did you check your strainer for blockage and presence of gasket? 7.) Did you check your tranny cooler for blockage, end crushage? Hose clamp snuggness? 8.) Any other gauges giving wonky indications? |
|
wheels06
Newbie Joined: June-16-2008 Location: United States Status: Offline Points: 10 |
Post Options
Thanks(0)
|
Bri892001,
1. Correct 2. No 3. it's too hot to put my hand on, not just the gauge. 4. Impeller was done correctly with a PCM. It didn't have a paper gasket, but I made one. There is no leakage from pump. 5. No quick flush kit that I can tell. 6. BINGO! Gasket is missing. Just called "local" dealer...30 miles away. They open at 10 and I'll be there at open and they have them in stock. 7. No, I didn't see anything that would be a problem. 8. All gauges are working fine. I can't thank you enough for your advice! This site is great for advice! I'll update results tomorrow! Thanks again! |
|
Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
Post Options
Thanks(0)
|
Nice!
Keep us posted. |
|
Hollywood
Moderator Group Joined: February-04-2004 Location: Twin Lakes, WI Status: Offline Points: 13514 |
Post Options
Thanks(0)
|
You might as well look in the bilge for that gasket. You can get two 10 packs of them from McMaster for the price of one PCM from a dealer.
|
|
MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3736 |
Post Options
Thanks(0)
|
I made a silicone gasket for my 78 Nautique, it worked for years. I filled the Oring slot with silicone, coated my cover with light grease where it would be touching the silicone. Installed the cover and let it dry. The cover still came off normally because the grease kept it from sticking closed. I used that gasket for years.
I think your lack of gasket created your issue. A minor air leak will give all of the symptoms you mentioned. Congratulations on a cheap fix although you had several headaches first. |
|
MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3736 |
Post Options
Thanks(0)
|
If your strainer is like mine, 95 GT40 Engine, a little synthetic grease on the threads will make installation much easier. The plastic on plastic threads are sticky and it is hard to tell when the strainer is actually tight or if you are just fighting sticky threads.
|
|
MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3736 |
Post Options
Thanks(0)
|
Hollywood, would you happen to have a part number for the McMaster source on the seals? Maybe what years it would cover? Thanks
|
|
Hollywood
Moderator Group Joined: February-04-2004 Location: Twin Lakes, WI Status: Offline Points: 13514 |
Post Options
Thanks(0)
|
9875K29. Same diameter canister, and therefore gasket, for the 1.25" big block strainer as well.
$8.78 for 10. I layed one of these over a PCM just last night and couldn't tell the difference. I also grease my threads, have come across some very stiff & sticky strainers. I typically boat in clean enough water to not need one but have been too lazy to cut a new hose from the hull to the trans cooler. |
|
MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3736 |
Post Options
Thanks(0)
|
Thanks for the part number, my GT 40 has the gasket that looks like it came off an oil filter. Both my Nautiques have run a water filter/strainer. They do catch leaves and things all the time. My Malibu had no strainer on the intake water line. I guess all the leaves just end up in the block or go out the exhaust?
|
|
Gary S
Grand Poobah Joined: November-30-2006 Location: Illinois Status: Offline Points: 14096 |
Post Options
Thanks(0)
|
Usually Mark they get caught in the trans cooler
|
|
Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
Post Options
Thanks(0)
|
If I was fighting a frustrating issue for a long time and I could fix it for under ten bucks before a summer holiday weekend, I'd be very happy man, even if said part could be had a little cheaper elsewhere.
So, did the original poster get his gasket and go skiing or what? |
|
JLags
Groupie Joined: September-05-2010 Location: Florida Status: Offline Points: 58 |
Post Options
Thanks(0)
|
So long story short, a new raw water pump did the trick. No more issues overheating even at idle There is still a bit more steam than it use to have but it seems to fine. Thank you everyone for helping.
|
|
Post Reply | Page <12 |
Tweet
|
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |