thermostat question

[smacks12]

hello,i'm constantly having to remove my thermostat on my volvo 4.3 gl to clean the seat. it seems like even the slightest debris keeps my engine from heating up to the normal temp. seems like the only time i see 170 degrees is for two or three runs, then its won't heat up untill i clean the thermostat again. is there any kind of engine flush that i can run through to safely clean the water side to help eliminate having to keep removing and cleaning the thermostat?

 

[now151]

Re: thermostat question

i wonder if a product like prestone radiator flush can be used? i've heard of people using muratic acid for flushing but its some bad stuff so i wouldn't recommend it. may do more damage than help. plus it would have to be contained and disposed of properly.

 

[boaterinsd]

Re: thermostat question

What are you finding in the t/ stat housing? Is it from the motor or the sea water?

 

[smacks12]

Re: thermostat question

i find very small pieces of flakey rust, like corrosion from the engine i assume. but its just enough to keep the thermostat from seating. sometimes when i take it out and look at it, i can barely see a sliver of light where its not seating all the way. i can't believe this little bit makes a difference in the temp. but it does.

 

[boaterinsd]

Re: thermostat question

interesting, i hope some of the BIG fish around here get to the bottom of this , i am wondering whats going on also.

 

[craze1cars]

Re: thermostat question

I have the exact same occasional issue with my 1999 VP 5.0 GL. About 2x per season I have to pull the T-stat, hit it with a heat gun to open it up, let the grit fall out of the seat, and reinstall. At about $1.98 each I buy T-stat gaskets by the dozen so I have extras laying around LOL...

But it is kinda annoying.

Mine also looks like it gets propped open by tiny little slivers of rust. I know it's time to open it up when my idle starts to stumble and I realize my gauge won't go past 120. After a quick cleanout my gauge shows a happy 165-ish and it runs great again.

I'm pretty sure it is rust flakes coming from the walls of the motor (mine has always been a freshwater boat, and is raw water cooled...but is now 12 years old). And I agree it takes a VERY little opening to prevent this motor from reaching operating temp...but I've found this more commonly a problem in the early season when water temp is in the 50's. When our water temp gets to 80-ish degrees mid summer I think the motor is able to warm up quicker and the t-stat can therefore open enough to flush itself out...I rarely need to do this in mid-summer, it's usually an early spring exercize.

If there's a cure or a prevention, it seems a couple of us are interested. But I'm guessing by the sound of crickets thusfar there is not a cure beyond a new motor, new risers, new manifold...etc. T-stat gaskets are much much cheaper LOL...

Any chance this is a possible disadvantage of dry storage? I never use antifreeze for storage...I always just drain it dry for winter...so the rust scale inside maybe dries and flakes off when water passes thru again in spring? I'm totally guessing...and obviously I dno't know how original poster stores his rig...

 

[pvancorenland]

Re: thermostat question

This might be a crazy idea, but would running the boat on muffs and revving the engine at say 2500 RPM allow the t-stat to open enough in your spring season to clean it out?
It would prevent the whole T-stat opening experience and burning your fingers on the heat gun

 

[edgebaker]

Re: thermostat question

my boat is a 2010 stingray... 20 hrs. has the volvo motor. and its doing the same thing. However, I need a little help. I dont know what to do to clean my thermo out, and where its located or what it looks like.... any help?

 

[Don S]

Re: thermostat question

Start here edgebaker http://forums.iboats.com/showthread.php?t=468283

 

[now151]

Re: thermostat question

i made a gasket out of a silicone oven cooking sheet. its about 1/16th thick and withstands heat over 4 hundred degrees that i reuse every time i pull the thermostat. i've pulled the therm. to clean about five times and reused it. it seems to be better than the one time use gaskets that are the replacement.

 

[Don S]

Re: thermostat question

i wonder if a product like prestone radiator flush can be used? i've heard of people using muratic acid for flushing but its some bad stuff so i wouldn't recommend it. may do more damage than help. plus it would have to be contained and disposed of properly.

i made a gasket out of a silicone oven cooking sheet. its about 1/16th thick and withstands heat over 4 hundred degrees that i reuse every time i pull the thermostat. i've pulled the therm. to clean about five times and reused it. it seems to be better than the one time use gaskets that are the replacement.

Danger.......... Danger..........Danger..........Danger..........Danger..........Danger..........

Please, do not give any more advise. You obviously have no clue of marine systems or what can happen when manifold to riser gaskets fail.

 

[now151]

Re: thermostat question

don, all i can say is that its working for me and all i did was make a comment about what i did. i'm sure your very smart and knowlegable, but don't try to be so insulting . i think most people including myself like to hear about what others do. you don't know me
or my experience level, but i am open minded. come down off the high pedestal

 

[craze1cars]

Re: thermostat question

I'm still tryin' to figure out what yer homemade T-stat gasket idea might do to create the riser-to-manifold gasket failure that Don refers to...??

Regardless, to get back on topic...several of us are still looking for additional ideas for a solution , or even a confirmed cause, of the original poster's (and others') repeating problem.

 

[now151]

Re: thermostat question

sorry for the misunderstanding. (warning) this gasket is homemade.