Thermostat Qs

Jarcher3

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May 9, 2016
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So i got my 01 larson 190 4.3GL after i had a shop diagnose an overheat issue. they replaced the impeller and the thermostat.

before they did this the engine stayed around the second or third tick form the bottom of the gauge.

after they did it it stayed at the second from overheat. but it did stay there and not overheat so i wasn't too worried about it.

I had been having power steering issues all summer and looked at the situation myself to save a shop charging for it and when i did this i found a bad impeller housing so i replaced it...after i did it ran at the high tick when idling but once on the open water it dropped to the first tick mark.. so now onto the actual question.

What is the temp rating of the 4.3gl thermostat? have i been running it too hot all summer?

on another and possibly related note, would running too hot cause any sort of oil burn?
when i had this shop(not too sure if i can trust them any more) look over the boat they said the engine and lower unit oil were perfect.. when i checked the oil after a low oil pressure alarm it was dark and low.... i just want to make sure i iron out the details and get it in tip top shape for next season

Thanks.
 

89retta

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What is the temp readings on the gauge? We don't know what gauge you have so one tick or two ticks mean nothing.
 

Jarcher3

Petty Officer 2nd Class
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May 9, 2016
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Im not sure it doesnt have the actual numbers on there is is just the tick marks with a cold and hot on either end
 

Fun Times

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01 Larson 190 4.3GL
There should be another letter or two after the GL such as 4.3GL-JF for example...It's best to know that info when working on your engine model. There should be a sticker/tag somewhere on the engine with this model number on it...There should also be an engine serial number and or product number too. To confirm the correct parts catalog for your engine you'll/we'll need them. http://www.volvopentastore.com/mall/...enta/help.html

That mentioned, it looks like the majority of the 4.3's used a 150 degree thermostat part number 3587597
http://www.ebay.com/itm/NEW-Volvo-Pe...3D180939119278

http://www.ebay.com/itm/Volvo-Penta-...1XKNAl&vxp=mtr

Have a photo of your temp gauge to help get an indication of your temp readings?
You'll also want to invest in owning an infrared laser temperature gun. http://www.harborfreight.com/non-con...ing-60725.html
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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ok, so you have a picture of your dash. why are you showing a picture of your dash? based on your gauges you could have an outboard or a big block inboard or the claimed 4.3

depending if your motor is carbureted, heat exchanged cooled or fuel injected or fuel injected with a heat exchanger and catalyzed exhaust, the thermostat operating temperature changes.

generally carbs are 140-150
heat exchanged motor or fuel injected and raw water are 160-170
fuel injected with MPI will runn about 170-180
fuel injection with cats and heat exchanger - 190
the specific thermostat for your motor will be in the service manual.

you can find an on-line version of your service manual here http://boatinfo.no/lib/library.html

you can order a factory service manual here http://www.volvopenta.com/volvopent...lication_search/Pages/publication_search.aspx

and yes, overheating your motor will coke the oil. and yes, if the shop said its good to go and you were low, find a new mechanic.
 
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Jarcher3

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Fun times had mentioned that a picture of the gauges might help for reference to my first post of the tick marks and that was the best picture that i had of the gauges.

the motor is a 4.3l v6 I/O volvo penta with an SX single prop outdrive it is a carborated engine with raw water cooling.

Thanks for all the help guys. ill look into the thermostat in the off season and see what temp it is.

That mechanic was the first one i could find with an opening that would work on volvos and now i know why.... i will be using the shop that partners with my marina as they have already been more than helpful and shown to be more knowledgeable
 

Fun Times

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ok, so you have a picture of your dash. why are you showing a picture of your dash?
The reason for the dash photo stimulated from the question in post number 2 then 3. Figured maybe it would help to get an idea of what he has to go by as for a temp reading.;)

Without numbers on the gauge can make it a bit more challenging to keep an general idea of what the engine seems to running at temp wise.

Jarcher3, in order for you to get to know "your" gauge better, you may want to try starting with a cold engine at idle, use an infrared laser temperature gun at the thermostat housing and watch the temperature rise both on the gauge and temp gun and see what each line on the gauge seems to indicate.

Generally the gauges may start off at 100 degrees and each line could be 20 degrees. So possibly the old thermostat may have been stuck open not allowing the engine to warm up in a normal time frame if it stayed closer to the "second tick form the bottom of the gauge" most of the time.
With the new thermostat running near the second tick from overheat should be more around the 160 mark which is considered okay if true being a 150 degree thermostat.

Where the temp gauge is a at rest in the photo above, is that where it normally rests at while cold 'engine off" ?... Is Key on or Key Off ??

Also if possible, what is the thermostat part number written on the service work order?

i found a bad impeller housing so i replaced it...after i did it ran at the high tick when idling but once on the open water it dropped to the first tick mark..
So you went from almost 200 degrees down to around 100 degrees once you gave the engine more RPM? If so then something sounds to be wrong... Also was it running a high temp while on the garden hose at home? Or at idle in the lake?

If the impeller was disintegrated then chances are parts of the impeller are stuck somewhere in the cooling passage system causing blockage.

It's best that you back flush the cooling system to try find and remove all the old impeller pieces... Also remove and inspect the thermostat housing as you probably have rubber impeller pieces sticking the thermostat closed or blocking the very small 'hard to locate bypass hole within the thermostat housing as that is a common issue.
 
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Jarcher3

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Where the temp gauge is a at rest in the photo above, is that where it normally rests at while cold 'engine off" ?... Is Key on or Key Off ??

That is key off (radio only on)

Also if possible, what is the thermostat part number written on the service work order?

Ill check when i get home


So you went from almost 200 degrees down to around 100 degrees once you gave the engine more RPM? If so then something sounds to be wrong... Also was it running a high temp while on the garden hose at home? Or at idle in the lake?

The high temp was idling at the dock,(which has been the normal temp all summer running it) then when i got out of the no wake zone and punched it the 75deg water cooled it off i guess.
 

Jarcher3

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Fun Times the thermostat per the service order was sierra number 18-3617 the only thing i could see online as far as temp rating was "go2marine" website that said the application was for a 8.1L Raw Water Cooled Engine (160?) the rest i couldnt find the temp rating.
 

Fun Times

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Fun Times the thermostat per the service order was sierra number 18-3617 the only thing i could see online as far as temp rating was "go2marine" website that said the application was for a 8.1L Raw Water Cooled Engine (160?) the rest i couldnt find the temp rating.
:) Now we need your full engine model number and or serial number to confirm the part number I posted above is correct vs guessing.

But it looks like they may have installed the wrong thermostat by part number and design/fit. If the correct OEM part number is 3587597 then the aftermarket sierra number would be 18-3615 THERMOSTAT - RAW WATER
Replaces: 3587597
150? Degrees.
Sierra Marine Thermostat is equivalent to parts:
  • 3587597 Volvo Penta
  • 3587597 Evinrude Johnson OMC BRP
Where like you found Sierra 18-3617 would be for an 8.1l that requires 160 degrees and has a different design/fit within the thermostat housings.
^ Application: 8.1L Raw Water Cooled Engine (160?)

Again, try to find your full engine model/info.
 

Jarcher3

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Fun Times

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Your correct OEM thermostat part number is 3856961...Not the one I found above at 150 degrees as that is for engines made after 2002.

3856961 is a 160 degree thermostat and the Sierra cross reference kit number is 18-3677 available through iboats if interested, http://www.iboats.com/Volvo-3856961-...view_id.467891

Though they're both 160 degree thermostats, Since it seems you may have a cooling issue someplace, you still want to install a correct part number thermostat to help narrow down where the issue may lie...If any... Also get to know your gauge while using the Temp laser gun mentioned above. Plus you need to inspect the insides of the thermostats housing for debris.

Parts Notes: 18-3677 THERMOSTAT KIT 160? Replaces: OMC 3856961
(If you prefer Volvo OEM vs aftermarket parts, Volvo doesn't have a "kit" like Sierra, so you'd need to order each part individually.)
? CONTAINS ?
Part # O.E.# Desc.
Sierra # 18-7170 = Volvo OEM # 3852071 O-Ring
Sierra # 18-2917 = Volvo OEM # 3852111 Thermostat Gasket
?-------- Volvo OEM # 3856961 Thermostat
[FONT=helvetica,Arial, Helvetica, sans-serif]4.3 (All Models)[/FONT]
[FONT=helvetica,Arial, Helvetica, sans-serif]MD,HU,NC,LK,[/FONT]
[FONT=helvetica,Arial, Helvetica, sans-serif]BY,WT,EF[/FONT]
[FONT=helvetica,Arial, Helvetica, sans-serif]1993-2000[/FONT]
[FONT=helvetica,Arial, Helvetica, sans-serif]NSS[/FONT]
[FONT=helvetica,Arial, Helvetica, sans-serif]18-7170[/FONT]
[FONT=helvetica,Arial, Helvetica, sans-serif]18-2917[/FONT]
[FONT=helvetica,Arial, Helvetica, sans-serif]18-3677-----------------[/FONT]
[FONT=helvetica,Arial, Helvetica, sans-serif]4.3 (All Models)[/FONT]
[FONT=helvetica,Arial, Helvetica, sans-serif]A, B[/FONT]
[FONT=helvetica,Arial, Helvetica, sans-serif]2001-2002[/FONT]
[FONT=helvetica,Arial, Helvetica, sans-serif]NSS[/FONT]
[FONT=helvetica,Arial, Helvetica, sans-serif]18-7170[/FONT]
[FONT=helvetica,Arial, Helvetica, sans-serif]18-2917[/FONT]
[FONT=helvetica,Arial, Helvetica, sans-serif]18-3677---------------------[/FONT]
[FONT=helvetica,Arial, Helvetica, sans-serif]C, D, E, F, G, J [/FONT]
[FONT=helvetica,Arial, Helvetica, sans-serif]2002-Current[/FONT]
[FONT=helvetica,Arial, Helvetica, sans-serif]NSS[/FONT]
[FONT=helvetica,Arial, Helvetica, sans-serif]NSS[/FONT]
[FONT=helvetica,Arial, Helvetica, sans-serif]18-2917[/FONT]
[FONT=helvetica,Arial, Helvetica, sans-serif]18-3615[/FONT]
[FONT=helvetica,Arial, Helvetica, sans-serif]18-3618[/FONT]
[FONT=helvetica,Arial, Helvetica, sans-serif]4.3 (All Models).[/FONT]
 

Jarcher3

Petty Officer 2nd Class
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Messages
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Thank you so much, now i can get this all sorted out before next season.
 

rkilpa

Petty Officer 3rd Class
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Oct 16, 2009
Messages
78
If the impeller was disintegrated then chances are parts of the impeller are stuck somewhere in the cooling passage system causing blockage.

It's best that you back flush the cooling system to try find and remove all the old impeller pieces... Also remove and inspect the thermostat housing as you probably have rubber impeller pieces sticking the thermostat closed or blocking the very small 'hard to locate bypass hole within the thermostat housing as that is a common issue.

+1. Do this!

If your temperature gauge fluctuates greatly when accelerating from idle, you have impeller pieces stuck inside the passages of the TS housing.
 

89retta

Senior Chief Petty Officer
Joined
Jul 18, 2010
Messages
772
If you want to check your thermostat. Place it in a pot of water on the stove with a candy thermometer. And watch at what temp it opens at.
 
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